Method and apparatus for information transmission in wireless communication system

ABSTRACT

According to one embodiment, a method for transmitting, by a user equipment (UE), information in a wireless communication system includes: determining a first information sequence based on a first cyclically shifted base sequence and a first orthogonal sequence by using a first physical uplink control channel (PUCCH) resource for a first antenna, wherein the first PUCCH resource is obtained based on a channel control element (CCE) index related to a physical downlink control channel (PDCCH) and a parameter configured by a higher layer; determining a second information sequence based on a second cyclically shifted base sequence and a second orthogonal sequence by using a second PUCCH resource for a second antenna, wherein the second PUCCH resource is obtained by adding an offset to the first PUCCH resource; transmitting the first information sequence via the first antenna; and transmitting the second information sequence via the second antenna.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/129,113, filed May 12, 2011, now U.S. Pat. No. 8,743,783, which isthe National Stage filing under 35 U.S.C. 371 of InternationalApplication No. PCT/KR2009/006723, filed on Nov. 16, 2009, which claimsthe benefit of U.S. Provisional Application Ser. No. 61/114,479, filedon Nov. 14, 2008, 61/114,480, filed on Nov. 14, 2008, 61/118,472, filedon Nov. 27, 2008, 61/118,473, filed on Nov. 27, 2008, 61/151,515, filedon Feb. 11, 2009, and 61/241,364, filed on Sep. 10, 2009, the contentsof which are all hereby incorporated by reference herein in theirentirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to wireless communications, and moreparticularly, to a method and apparatus for information transmission ina wireless communication system.

Related Art

Wireless communication systems are widely spread all over the world toprovide various types of communication services such as voice or data.The wireless communication system is designed for the purpose ofproviding reliable communication to a plurality of users irrespective oftheir locations and mobility. However, a wireless channel has anabnormal characteristic such as a fading phenomenon caused by a pathloss, noise, and multipath, an inter-symbol interference (ISI), aDoppler effect caused by mobility of a user equipment, etc. Therefore,various techniques have been developed to overcome the abnormalcharacteristic of the wireless channel and to increase reliability ofwireless communication.

A multiple input multiple output (MIMO) scheme is used as a techniquefor supporting a reliable high-speed data service. The MIMO scheme usesmultiple transmit antennas and multiple receive antennas to improve datatransmission/reception efficiency. Examples of the MIMO scheme includespatial multiplexing, transmit diversity, beamforming, etc. A MIMOchannel matrix depending on the number of receive antennas and thenumber of transmit antennas can be decomposed into a plurality ofindependent channels. Each independent channel is referred to as atransmission layer or a stream. The number of transmission layers isreferred to as a rank.

Meanwhile, there is an ongoing standardization effort for aninternational mobile telecommunication-advanced (IMT-A) system aiming atthe support of an Internet protocol (IP)-based multimedia seamlessservice by using a high-speed data transfer rate of 1 gigabits persecond (Gbps) in a downlink and 500 megabits per second (Mbps) in anuplink in the international telecommunication union (ITU) as a nextgeneration (i.e., post 3^(rd) generation) mobile communication system. A3^(rd) generation partnership project (3GPP) is considering a 3GPP longterm evolution-advanced (LTE-A) system as a candidate technique for theIMT-A system. It is expected that the LTE-A system is developed tofurther complete an LTE system while maintaining backward compatibilitywith the LTE system. This is because the support of compatibilitybetween the LTE-A system and the LTE system facilitates userconvenience. In addition, the compatibility between the two systems isalso advantageous from the perspective of service providers since theexisting equipment can be reused.

A typical wireless communication system is a single-carrier systemsupporting one carrier. Since a data transfer rate is in proportion to atransmission bandwidth, the transmission bandwidth needs to increase tosupport a high-speed data transfer rate. However, except for some areasof the world, it is difficult to allocate frequencies of widebandwidths. For the effective use of fragmented small bands, a spectrumaggregation technique is being developed. The spectrum aggregation isalso referred to as bandwidth aggregation or carrier aggregation. Thespectrum aggregation technique is a technique for obtaining the sameeffect as when a band of a logically wide bandwidth is used byaggregating a plurality of physically non-contiguous bands in afrequency domain. By using the spectrum aggregation technique, multiplecarriers can be supported in the wireless communication system. Thewireless communication system supporting the multiple carriers isreferred to as a multiple-carrier system. The multiple-carrier system isalso referred to as a carrier aggregation system. The carrier may alsobe referred to as other terms, such as, a radio frequency (RF), acomponent carrier (CC), etc.

For backward compatibility with the IMT system, a bandwidth of carriersused for carrier aggregation can be limited to a bandwidth supported inthe IMT system. Carriers of a bandwidth of {1.4, 3, 5, 10, 15, 20}[MHz(megahertz)] are supported in 3GPP LTE. Therefore, LTE-A can support abandwidth greater than 20 MHz by aggregating carriers of the bandwidthsupported in the 3GPP LTE. Alternatively, irrespective of the bandwidthsupported in the legacy system, a carrier of a new bandwidth can bedefined to support carrier aggregation.

Time division multiplexing (TDM), frequency division multiplexing (FDM),code division multiplexing (CDM), or the like can be used as amultiplexing scheme for communication between a base station and each ofa plurality of user equipments. The CDM and/or the FDM may be used forsimultaneous communication between the base station and each of theplurality of user equipments.

A resource for wireless communication is any one or more combinations of(1) time, (2) frequency, and (3) sequence according to a multiplexingscheme. In case of a multiple input multiple output (MIMO) system or amulti-carrier system, there may be a need for allocating multipleresources to one user equipment (UE). A method capable of effectivelyallocating multiple resources to one UE is necessary due to limitedresources. There is a need for a method and apparatus for effectivelyallocating multiple resources and for effectively transmittinginformation.

SUMMARY OF THE INVENTION

The present invention provides a method and apparatus for informationtransmission in a wireless communication system.

In an aspect, a method for information transmission performed by atransmitter in a wireless communication system is provided. The methodinclude acquiring a first resource index and a second resource index,generating information sequences based on the first resource index andthe second resource index, and transmitting the information sequencesthrough a first antenna and a second antenna, wherein the secondresource index is acquired from the first resource index and an offset.

According to the present invention, a method and apparatus for effectiveinformation transmission is provided in a wireless communication system.Therefore, overall system performance can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a wireless communication system.

FIG. 2 is a diagram showing a radio protocol architecture for a userplane.

FIG. 3 is a diagram showing a radio protocol architecture for a controlplane.

FIG. 4 shows a structure of a radio frame.

FIG. 5 shows an example of a resource grid for one UL slot.

FIG. 6 shows a structure of a DL subframe.

FIG. 7 shows an exemplary structure of a UL subframe.

FIG. 8 is a block diagram showing an exemplary structure of atransmitter.

FIG. 9 shows an example of a plurality of carriers used in amultiple-carrier system.

FIG. 10 is a block diagram showing an exemplary structure of aninformation processor included in a transmitter.

FIG. 11 shows an example of PUCCH format 1/1a/1b transmission in case ofa normal CP.

FIG. 12 shows an example of PUCCH format 1/1a/1b transmission in case ofan extended CP.

FIG. 13 shows an example of PUCCH format 2 transmission when a normal CPis used.

FIG. 14 shows an example of PUCCH format 2 transmission when an extendedCP is used.

FIG. 15 is a block diagram showing an exemplary structure of atransmitter including two antennas.

FIG. 16 is a block diagram showing an exemplary structure of a part of atransmitter including two antennas.

FIG. 17 is a block diagram showing another exemplary structure of a partof a transmitter including two antennas.

FIG. 18 is a flowchart showing an example of a method for informationtransmission through two antennas in a transmitter according to anembodiment of the present invention.

FIG. 19 shows an example of a method of multiplexing a plurality ofPDCCHs for a plurality of UEs by a BS.

FIG. 20 shows an example of a multi-carrier system having a symmetricstructure.

FIG. 21 shows an example of a multi-carrier system having an asymmetricstructure.

FIG. 22 is a block diagram showing wireless communication system toimplement an embodiment of the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following technique may be used for various wireless communicationsystems such as code division multiple access (CDMA), a frequencydivision multiple access (FDMA), time division multiple access (TDMA),orthogonal frequency division multiple access (OFDMA), singlecarrier-frequency division multiple access (SC-FDMA), and the like. TheCDMA may be implemented as a radio technology such as universalterrestrial radio access (UTRA) or CDMA2000. The TDMA may be implementedas a radio technology such as a global system for mobile communications(GSM)/general packet radio service (GPRS)/enhanced data rates for GSMevolution (EDGE). The OFDMA may be implemented by a radio technologysuch as IEEE (Institute of Electrical and Electronics Engineers) 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, E-UTRA (Evolved UTRA), andthe like. The UTRA is part of a universal mobile telecommunicationssystem (UMTS). 3GPP (3^(rd) Generation, Partnership Project) LTE (LongTerm Evolution) is part of an evolved UMTS (E-UMTS) using the E-UTRA,which employs the OFDMA in downlink and the SC-FDMA in uplink. LTE-A(Advanced) is an evolution of 3GPP LTE.

Hereinafter, for clarification, LTE-A will be largely described, but thetechnical concept of the present invention is not meant to be limitedthereto.

FIG. 1 shows a wireless communication system.

Referring to FIG. 1, a wireless communication system 10 includes atleast one base station (BS) 11. Respective BSs 11 provide communicationservices to specific geographical regions (generally referred to ascells) 15 a, 15 b, and 15 c. The cell can be divided into a plurality ofregions (referred to as sectors). A user equipment (UE) 12 may be fixedor mobile, and may be referred to as another terminology, such as amobile station (MS), a user terminal (UT), a subscriber station (SS), awireless device, a personal digital assistant (PDA), a wireless modem, ahandheld device, etc. The BS 11 is generally a fixed station thatcommunicates with the UE 12 and may be referred to as anotherterminology, such as an evolved node-B (eNB), a base transceiver system(BTS), an access point, etc.

Hereinafter, a downlink (DL) implies communication from the BS to theUE, and an uplink (UL) implies communication from the UE to the BS. Inthe DL, a transmitter may be a part of the BS, and a receiver may be apart of the UE. In the UL, the transmitter may be a part of the UE, andthe receiver may be a part of the BS.

A heterogeneous network implies a network in which a relay station, afemto cell and/or a pico cell, and the like are deployed. In theheterogeneous network, the DL may imply communication from the BS to therelay station, the femto cell, or the pico cell. Further, the DL mayalso imply communication from the relay station to the UE. Furthermore,in case of multi-hop relay, the DL may imply communication from a firstrelay station to a second relay station. In the heterogeneous network,the UL may imply communication from the relay station, the femto cell,or the pico cell to the BS. Further, the UL may also imply communicationfrom the UE to the relay station. Furthermore, in case of multi-hoprelay, the UL may imply communication from the second relay station tothe first relay station.

The wireless communication system can support multiple antennas. Thetransmitter may use a plurality of transmit (Tx) antennas, and thereceiver may use a plurality of receive (Rx) antennas. The Tx antennadenotes a physical or logical antenna used for transmission of onesignal or stream. The Rx antenna denotes a physical or logical antennaused for reception of one signal or stream. When the transmitter and thereceiver use a plurality of antennas, the wireless communication systemmay be referred to as a multiple input multiple output (MIMO) system.

The wireless communication system can support UL and/or DL hybridautomatic repeat request (HARQ). In addition, a channel qualityindicator (CQI) can be used for link adaptation.

A wireless communication process is preferably implemented with aplurality of independent hierarchical layers rather than one singlelayer. A structure of a plurality of hierarchical layers is referred toas a protocol stack. The protocol stack may refer to an open systeminterconnection (OSI) model which is a widely known protocol forcommunication systems.

FIG. 2 is a diagram showing a radio protocol architecture for a userplane. FIG. 3 is a diagram showing a radio protocol architecture for acontrol plane. The user plane is a protocol stack for user datatransmission. The control plane is a protocol stack for control signaltransmission.

Referring to FIGS. 2 and 3, between different physical (PHY) layers(i.e., a PHY layer of a transmitter and a PHY layer of a receiver), datais transferred through a physical channel. The PHY layer is alsoreferred to as a layer 1 (L1). The PHY layer is coupled with a mediumaccess control (MAC) layer, i.e., an upper layer of the PHY layer,through a transport channel. Between the MAC layer and the PHY layer,data is transferred through the transport channel. The PHY layerprovides the MAC layer and an upper layer with an information transferservice through the transport channel.

The MAC layer provides services to a radio link control (RLC) layer,i.e., an upper layer of the MAC layer, through a logical channel. TheRLC layer supports reliable data transmission. A packet data convergenceprotocol (PDCP) layer performs a header compression function to reduce aheader size of an Internet protocol (IP) packet. The MAC layer, the RLClayer, and the PDCP layer are also referred to as a layer 2 (L2).

A radio resource control (RRC) layer is defined only in the controlplane. The RRC layer is also referred to as a layer 3 (L3). The RRClayer controls radio resources between a UE and a network. For this, inthe RRC layer, RRC messages are exchanged between the UE and thenetwork. The RRC layer serves to control the logical channel, thetransport channel, and the physical channel in association withconfiguration, reconfiguration and release of radio bearers. The radiobearer represents a logical path provided by the L1 and the L2 for datatransmission between the UE and the network. Configuration of the radiobearer implies a process for defining characteristics of a radioprotocol layer and channel to provide a specific service, and forconfiguring respective specific parameters and operation mechanisms. Theradio bearer can be classified into a signaling radio bearer (SRB) and adata radio bearer (DRB). The SRB is used as a path for transmitting anRRC message in the control plane, and the DRB is used as a path fortransmitting user data in the user plane. When an RRC connection isestablished between an RRC layer of the UE and an RRC layer of thenetwork, it is called that the UE is in an RRC connected mode. When theRRC connection is not established yet, it is called that the UE is in anRRC idle mode.

A non-access stratum (NAS) layer belongs to an upper layer of the RRClayer and serves to perform session management, mobility management, orthe like.

FIG. 4 shows a structure of a radio frame.

Referring to FIG. 4, the radio frame consists of 10 subframes. Onesubframe consists of two slots. Slots included in the radio frame arenumbered with slot numbers #0 to #19. A time required to transmit onesubframe is defined as a transmission time interval (TTI). The TTI maybe a scheduling unit for data transmission. For example, one radio framemay have a length of 10 milliseconds (ms), one subframe may have alength of 1 ms, and one slot may have a length of 0.5 ms.

The radio frame of FIG. 4 is shown for exemplary purposes only. Thus,the number of subframes included in the radio frame or the number ofslots included in the subframe may change variously.

FIG. 5 shows an example of a resource grid for one UL slot.

Referring to FIG. 5, the UL slot includes a plurality of orthogonalfrequency division multiplexing (OFDM) symbols in a time domain andincludes N(UL) resource blocks (RBs) in a frequency domain. The OFDMsymbol represents one symbol period, and may also be referred to asother terms such as an OFDMA symbol, an SC-FDMA symbol, or the likeaccording to a multiple access scheme. The number N(UL) of RBs includedin the UL slot depends on a UL transmission bandwidth determined in acell. One RB includes a plurality of subcarriers in the frequencydomain.

Each element on the resource grid is referred to as a resource element(RE). The RE on the resource grid can be identified by an index pair (k,l) in a slot. Herein, k(k=0, . . . , N(UL)×12−1) denotes a subcarrierindex in the frequency domain, and l(l=0, . . . , 6) denotes a symbolindex in the time domain.

Although it is described herein that one RB includes 7×12 resourceelements consisting of 7 OFDM symbols in the time domain and 12subcarriers in the frequency domain for example, the number of OFDMsymbols and the number of subcarriers in the RB are not limited thereto.Thus, the number of OFDM symbols and the number of subcarriers maychange variously depending on a cyclic prefix (CP) length, a frequencyspacing, etc. For example, when using a normal CP, the number of OFDMsymbols is 7, and when using an extended CP, the number of OFDM symbolsis 6.

The resource grid for one UL slot of FIG. 5 can also be applied to aresource grid for a DL slot.

FIG. 6 shows a structure of a DL subframe.

Referring to FIG. 6, the DL subframe includes two consecutive slots.First 3 OFDM symbols of a 1^(st) slot included in the DL subframecorrespond to a control region, and the remaining OFDM symbolscorrespond to a data region. Herein, the control region includes 3 OFDMsymbols for exemplary purposes only.

A physical downlink shared channel (PDSCH) may be allocated to the dataregion. DL data is transmitted through the PDSCH. The DL data may be atransport block which is a data block for a downlink shared channel(DL-SCH), i.e., a transport channel transmitted during TTI. A BS maytransmit the DL data to a UE through one antenna or multiple antennas.In 3GPP LTE, the BS may transmit one codeword to the UE through oneantenna or multiple antennas, or may transmit two codewords throughmultiple antennas. The 3GPP LTE supports up to 2 codewords. Thecodewords are encoded bits in which channel coding is performed on aninformation bit corresponding to information. Modulation can beperformed for each codeword.

A control channel may be allocated to the control region. Examples ofthe control channel include a physical control format indicator channel(PCFICH), a physical hybrid automatic repeat request (HARQ) indicatorchannel (PHICH), a physical downlink control channel (PDCCH), etc.

The PCFICH carries information indicating the number of OFDM symbolsused for transmission of PDCCHs in a subframe to the UE. The number ofOFDM symbols used for PDCCH transmission may change in every subframe.In the subframe, the number of OFDM symbols used for PDCCH transmissionmay be any one value among 1, 2, and 3. If a DL transmission bandwidthis less than a specific threshold, the number of OFDM symbols used forPDCCH transmission in the subframe may be any one value among 2, 3, and4.

The PHICH carries HARQ acknowledgement (ACK)/negative acknowledgement(NACK) for UL data.

The control region consists of a set of a plurality of control channelelements (CCEs). If a total number of CCEs constituting a CCE set isN(CCE) in the DL subframe, the CCEs are indexed from 0 to N(CCE)-1. TheCCEs correspond to a plurality of resource elements groups. The resourceelement group is used to define mapping of the control channel to aresource element. One resource element group consists of a plurality ofresource elements. A PDCCH is transmitted through an aggregation of oneor several contiguous CCEs. A plurality of PDCCHs may be transmitted inthe control region. A PDCCH format and the number of available PDCCHbits are determined according to the number of CCEs constituting the CCEaggregation. Hereinafter, the number of CCEs used for PDCCH transmissionis referred to as a CCE aggregation level. The CCE aggregation level isa CCE unit for searching for the PDCCH. A size of the CCE aggregationlevel is defined by the number of contiguous CCEs. For example, the CCEaggregation level may be an element of {1, 2, 4, 8}.

The PDCCH carries DL control information. Examples of the DL controlinformation include DL scheduling information, UL schedulinginformation, a UL power control command, etc. The DL schedulinginformation is also referred to as a DL grant. The UL schedulinginformation is also referred to as a UL grant.

The BS does not provide the UE with information indicating where a PDCCHof the UE is located in the subframe. In general, in a state where theUE does not know a location of the PDCCH of the UE in the subframe, theUE finds the PDCCH of the UE by monitoring a set of PDCCH candidates inevery subframe. Monitoring implies that the UE attempts to performdecoding for each of the PDCCH candidates according to all possible DCIformats. This is referred to as blind decoding or blind detection.

For example, when the BS transmits the DL data to the UE through a PDSCHwithin a subframe, the BS carries a DL grant used for scheduling of thePDSCH through a PDCCH within the subframe. The UE can first detect thePDCCH for transmitting the DL grant through blind decoding. The UE canread the DL data transmitted through the PDSCH based on the DL grant.

FIG. 7 shows an exemplary structure of a UL subframe.

Referring to FIG. 7, the UL subframe can be divided into a controlregion and a data region. A physical uplink control channel (PUCCH) forcarrying UL control information is allocated to the control region. Aphysical uplink shared channel (PUSCH) for carrying user data isallocated to the data region. In 3GPP LTE (Release 8), resource blocksallocated to one UE are contiguous in a frequency domain to maintain asingle-carrier property. One UE cannot transmit the PUCCH and the PUSCHconcurrently. Concurrent transmission of the PUCCH and the PUSCH isunder consideration In LTE-A (Release 10).

The PUCCH for one UE is allocated in a resource block (RB) pair in thesubframe. RBs belonging to the RB pair occupy different subcarriers ineach of 1^(st) and 2^(nd) slots. A frequency occupied by the RBsbelonging to the RB pair to be allocated to the PUCCH is changed on aslot boundary basis. That is, RBs allocated to the PUCCH are hopped in aslot level. Hereinafter, hopping of the RB in the slot level is calledfrequency hopping. A frequency diversity gain is obtained when the UEtransmits UL control information through a frequency located atdifferent positions over time. In FIG. 7, m is a location indexindicating a frequency-domain location of the RB pair allocated to thePUCCH within the subframe.

The PUSCH is mapped to an uplink shared channel (UL-SCH) which is atransport channel. Examples of UL control information transmittedthrough the PUCCH include HARQ ACK/NACK, a channel quality indicator(CQI) indicating a DL channel state, a scheduling request (SR) as arequest for UL radio resource allocation, etc. Hereinafter, the CQI isthe concept including a precoding matrix indicator (PMI) and a rankindicator (RI) in addition to the CQI. The concept including the CQI,the PMI, and the RI is also called channel state information (CSI).

Time division multiplexing (TDM), frequency division multiplexing (FDM),code division multiplexing (CDM), or the like can be used as amultiplexing scheme for communication between a BS and each of aplurality of UEs. The CDM and/or the FDM may be used for simultaneouscommunication between the BS and each of the plurality of UEs.

Multiplexing schemes based on an orthogonal sequence or aquasi-orthogonal sequence are collectively referred to as the CDM. Thatis, sequences used for the CDM are not necessarily orthogonal to eachother. Sequences having a low correlation may also be used for the CDM.

Hereinafter, a method and apparatus for information transmission will bedescribed when CDM and/or FDM are used as a multiplexing scheme.

When the CDM and/or the FDM are used as the multiplexing scheme, aresource used for information transmission is a sequence and/or afrequency resource. For example, when only the CDM is used as themultiplexing scheme, the resource is the sequence, and when the CDM andthe FDM are used together, the resource is the sequence and thefrequency resource. Hereinafter, the frequency resource and the sequencewill be described in detail.

(1) Frequency Resource

The aforementioned resource block is an example of the frequencyresource. This is because the frequency resource differs when theresource block differs within the same time period. Hereinafter, forconvenience of explanation, the resource block is used in the concept ofa normal frequency resource.

(2) Sequence

The sequence is not particularly limited, and thus may be any sequence.

For example, the sequence may be selected from a sequence set having aplurality of sequences as its elements. The plurality of sequencesincluded in the sequence set may be orthogonal to each other, or mayhave a low correlation with each other. For convenience of explanation,it is assumed that the plurality of sequences included in the sequenceset is orthogonal to each other. Hereinafter, the sequence set is anorthogonal sequence set consisting of orthogonal sequences. Each of theorthogonal sequences belonging to the orthogonal sequence setcorresponds to one orthogonal sequence index in a one-to-one manner.

The orthogonal sequence set having length-4 orthogonal sequences as itselements may use a Walsh-Hadamard matrix. Table 1 below shows an exampleof an orthogonal sequence set consisting of an orthogonal sequence w(k,Ios) having a length of K=4 (Ios denotes an orthogonal sequence indexand k denotes an element index of the orthogonal sequence, where0≦k≦K−1).

TABLE 1 Orthogonal sequence index [w(0), w(1), w(2), w(3)] 0 [+1 +1 +1+1] 1 [+1 −1 +1 −1] 2 [+1 +1 −1 −1] 3 [+1 −1 −1 +1]

The orthogonal sequence set may consist of only some orthogonalsequences of Table 1 above. In 3GPP LTE, three orthogonal sequences areused except for [+1, +1, −1, −1].

Table 2 below shows an example of an orthogonal sequence set consistingof an orthogonal sequence w(k, Ios) having a length of K=3 (Ios denotesan orthogonal sequence index and k denotes an element index of theorthogonal sequence, where 0≦k≦K−1).

TABLE 2 Orthogonal sequence index [w(0), w(1), w(2)] 0 [1 1 1] 1 [1e^(j2π/3) e^(j4π/3)] 2 [1 e^(j4π/3) e^(j2π/3)]

Table 3 below shows an example of an orthogonal sequence set consistingof an orthogonal sequence w(k, Ios) having a length of K=2 (Ios denotesan orthogonal sequence index and k denotes an element index of theorthogonal sequence, where 0≦k≦K−1).

TABLE 3 Orthogonal sequence index [w(0), w(1)] 0 [1 1] 1 [1 −1]

For another example, a cyclically shifted sequence may be used as thesequence. The cyclically shifted sequence can be generated by cyclicallyshifting a base sequence by a specific cyclic shift (CS) amount. Varioustypes of sequences can be used as the base sequence. For example, awell-known sequence such as a pseudo noise (PN) sequence and aZadoff-Chu (ZC) sequence can be used as the base sequence.Alternatively, a computed generated constant amplitude zeroauto-correlation (CAZAC) sequence may be used. Equation 1 below shows anexample of the base sequence.

r _(i)(n)=e ^(jb(n)π/4)  

Equation 1

Herein, iε{0, 1, . . . , 29}denotes a root index, and n denotes acomponent index in the range of 0≦n≦N−1, where N is a sequence length. ican be determined by a cell identifier (ID), a slot number in a radioframe, etc. When one resource block includes 12 subcarriers, N can beset to 12. A different base sequence is defined according to a differentroot index. When N=12, b(n) can be defined by Table 4 below.

TABLE 4 i b(0), . . . , b(11) 0 −1 1 3 −3 3 3 1 1 3 1 −3 3 1 1 1 3 3 3−1 1 −3 −3 1 −3 3 2 1 1 −3 −3 −3 −1 −3 −3 1 −3 1 −1 3 −1 1 1 1 1 −1 −3−3 1 −3 3 −1 4 −1 3 1 −1 1 −1 −3 −1 1 −1 1 3 5 1 −3 3 −1 −1 1 1 −1 −1 3−3 1 6 −1 3 −3 −3 −3 3 1 −1 3 3 −3 1 7 −3 −1 −1 −1 1 −3 3 −1 1 −3 3 1 81 −3 3 1 −1 −1 −1 1 1 3 −1 1 9 1 −3 −1 3 3 −1 −3 1 1 1 1 1 10 −1 3 −1 11 −3 −3 −1 −3 −3 3 −1 11 3 1 −1 −1 3 3 −3 1 3 1 3 3 12 1 −3 1 1 −3 1 1 1−3 −3 −3 1 13 3 3 −3 3 −3 1 1 3 −1 −3 3 3 14 −3 1 −1 −3 −1 3 1 3 3 3 −11 15 3 −1 1 −3 −1 −1 1 1 3 1 −1 −3 16 1 3 1 −1 1 3 3 3 −1 −1 3 −1 17 −31 1 3 −3 3 −3 −3 3 1 3 −1 18 −3 3 1 1 −3 1 −3 −3 −1 −1 1 −3 19 −1 3 1 31 −1 −1 3 −3 −1 −3 −1 20 −1 −3 1 1 1 1 3 1 −1 1 −3 −1 21 −1 3 −1 1 −3 −3−3 −3 −3 1 −1 −3 22 1 1 −3 −3 −3 −3 −1 3 −3 1 −3 3 23 1 1 −1 −3 −1 −3 1−1 1 3 −1 1 24 1 1 3 1 3 3 −1 1 −1 −3 −3 1 25 1 −3 3 3 1 3 3 1 −3 −1 −13 26 1 3 −3 −3 3 −3 1 −1 −1 3 −1 −3 27 −3 −1 −3 −1 −3 3 1 −1 1 3 −3 −328 −1 3 −3 3 −1 3 3 −3 3 3 −1 −1 29 3 −3 −3 −1 −1 −3 −1 3 −3 3 1 −1

The base sequence r(n) can be cyclically shifted according to Equation 2below to generate a cyclically shifted sequence r(n, Ics).

$\begin{matrix}{{{r\left( {n,I_{cs}} \right)} = {{r(n)} \cdot {\exp \left( \frac{j\; 2\pi \; I_{cs}n}{N} \right)}}},{0 \leq I_{cs} \leq {N - 1}}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

In Equation 2, Ics denotes a CS index indicating a CS amount (0≦Ics≦N−1,where Ics is an integer).

Hereinafter, an available CS index of the base sequence denotes a CSindex that can be derived from the base sequence according to a CSinterval. For example, if a length of the base sequence is 12 and the CSinterval is 1, a total number of available CS indices of the basesequence are 12. Alternatively, if a length of the base sequence is 12and the CS interval is 2 a total number of available CS indices of thebase sequence is 6. The CS interval can be determined by considering adelay spread.

FIG. 8 is a block diagram showing an exemplary structure of atransmitter. Herein, the transmitter may be a part of a UE or a BS.

Referring to FIG. 8, a transmitter 100 includes an information processor110, a reference signal generator 120, a resource block mapper 130, anOFDM signal generator 140, a radio frequency (RF) unit 150, and anantenna 190.

The information processor 110 and the reference signal generator 120 areconnected to the resource block mapper 130. The resource block mapper130 is connected to the OFDM signal generator 140. The OFDM signalgenerator 140 is connected to the RF unit 150. The RF unit 150 isconnected to the antenna 190.

Information is input to the information processor 110. Examples of theinformation include user data, control information, mixed information ofseveral pieces of control information, multiplexed information of thecontrol information and the user data, etc. The information may have abit or bit-stream format. The transmitter 100 can be implemented in aphysical layer. In this case, the information may be derived from ahigher layer such as a MAC layer.

The information processor 110 is configured to generate an informationsequence based on information or a sequence. The information sequenceconsists of a plurality of information sequence elements.

The reference signal generator 120 generates a reference signalsequence. The reference signal sequence consists of a plurality ofreference signal elements. The reference signal sequence can also bereferred to as a reference signal (RS). The RS is a signal which isknown to both a transmitter and a receiver. The RS can be used forinformation demodulation in the receiver. Any sequence can be used asthe RS sequence without a particular restriction.

The resource block mapper 130 is configured to map the informationsequence and the RS sequence to a resource block allocated forinformation transmission. One information sequence element or one RSsequence element can be mapped to one resource element. ‘0’ may beinserted to a resource element to which the information sequence and theRS sequence are not mapped. Since CDM is used, multiplexing can beachieved to the same resource block. Of course, FDM can be used togetherwith the CDM, and thus multiplexing can be achieved by differentresource blocks.

The resource block may be a physical resource block or a virtualresource block. The physical resource block includes subcarriersphysically located in a frequency domain. The virtual resource blockincludes subcarriers physically distributed in the frequency domain.There is no particular restriction on a distribution scheme ofsubcarriers included in the virtual resource block.

For information transmission, one or more resource blocks may beallocated to the transmitter 100. When a plurality of resource blocksare allocated, the plurality of resource blocks may be allocated eithercontinuously or discontinuously. When the information sequence and theRS sequence are mapped to subcarriers in a localized mapping type or adistributed mapping type, a single-carrier property is maintained. Thelocalized mapping type is that the information sequence and the RSsequence are mapped to subcarriers physically contiguous in thefrequency domain. The distributed mapping type is that the informationsequence and the RS sequence are mapped to subcarriers distributedequidistantly. In 3GPP LTE, the localized mapping type is used in ULtransmission.

The resource block includes an information part and an RS part. Theinformation sequence is mapped to the information part, and the RSsequence is mapped to the RS part.

The RS part and the information part may use different OFDM symbolswithin a resource block. Alternatively, the RS part and the informationpart may use different subcarriers within an OFDM symbol.

For convenience of explanation, it is assumed hereinafter that the RSpart and the information part use different OFDM symbols within theresource block. One or more OFDM symbols within the resource block maybe the RS part. When a plurality of OFDM symbols within the resourceblock is the RS part, the plurality of OFDM symbols may be contiguous toeach other or may be non-contiguous to each other. The position andnumber of OFDM symbols used as the RS part within the resource block mayvary without a particular restriction. An OFDM symbol within theresource block except for the RS part may be used as the informationpart.

For example, it is assumed that the transmitter is a part of a UE, andtransmits information through a PUCCH. The resource block mapper 130maps the information sequence and the RS sequence to a resource blockpair (see FIG. 7) within a subframe allocated for PUCCH transmission.

The OFDM signal generator 140 is configured to generate atime-continuous OFDM signal in every OFDM symbol within the resourceblock. The time-continuous OFDM signal is also referred to as an OFDMbaseband signal. The OFDM signal generator 140 can generate an OFDMsignal by performing an inverse fast Fourier transform (IFFT) operation,CP insertion, or the like for each OFDM symbol.

The RF unit 150 converts the OFDM baseband signal to a radio signal. TheOFDM baseband signal can be converted to the radio signal by beingup-converted to a carrier frequency. The carrier frequency is alsoreferred to as a center frequency. The radio signal is transmittedthrough the antenna 190.

The transmitter 100 can support both a single-carrier system and amultiple-carrier system. When supporting the multiple-carrier system,the transmitter 100 may include the information processor 110, thereference signal generator 120, the resource block mapper 130, the OFDMsignal generator 140, or the RF unit 150 for each carrier.

Hereinafter, the OFDM signal can use not only OFDMA but also SC-FDMA andclustered SC-FDMA which is modification of SC-FDMA, NxSC-FDMA, or thelike as a multiple access scheme.

The SC-FDMA is also referred to as DFT spread-OFDM (DFTs-OFDM) sinceIFFT is performed on DFT-spread complex-valued symbols. In the SC-FDMA,a peak-to-average power ration (PAPR) or a cubic metric (CM) may bedecreased. When using the SC-FDMA transmission scheme, transmissionpower efficiency may be increased in a UE of which power consumption islimited. Accordingly, a user throughput can be increased.

The clustered SC-FDMA is a method in which the DFT-spread complex-valuedsymbols are divided into a plurality of subblocks, and the plurality ofsubblocks is mapped to subcarriers by being distributed in a frequencydomain. This is also referred to as clustered DFTs-OFDM. The clusteredSC-FDMA is applicable to both the single-carrier system and themultiple-carrier system. In the multiple-carrier system, one subblockmay correspond to one subcarrier. When carriers are continuouslyallocated in the multiple-carrier system, and a subcarrier spacing isaligned between consecutive carriers, then the transmitter 100 mayinclude one OFDM signal generator 140 and one antenna 190. When thecarriers are allocated non-continuously and the subcarrier spacing isnot aligned between the contiguous carriers, the transmitter 100 mayinclude the OFDM signal generator 140 and the RF unit 150 for eachcarrier.

The NxSC-FDMA is a method in which a codeblock is divided into aplurality of chunks and DFT and IFFT are performed on a chunk basis.This is also referred to as chunk specific DFTs-OFDM. The transmitter100 may include the information processor 110, the reference signalgenerator 120, the resource block mapper 130, the OFDM signal generator140, and the RF unit 150 for each carrier. The NxSC-FDMA is applicableto both continuous carrier allocation and non-contiguous carrierallocation.

FIG. 9 shows an example of a plurality of carriers used in amultiple-carrier system.

Referring to FIG. 9, the multiple-carrier system may use N carriers,i.e., CC #1, CC #2, . . . , CC #N. It is shown herein that adjacentcarriers are physically discontinuous in a frequency domain. However,this is for exemplary purposes only, and thus the adjacent carriers maybe physically contiguous in the frequency domain. Therefore, themultiple-carrier system may use a frequency of a logically largebandwidth (BW) by aggregating a plurality of carriers physicallycontiguous and/or non-contiguous in the frequency domain.

In the multiple-carrier system, a physical layer can be implemented percarrier. Alternatively, one physical layer can be implemented for aplurality of carriers. In this case, one physical layer may manage oroperate the plurality of carriers. A MAC layer may also be implementedper carrier, or one MAC layer may be implemented for a plurality ofcarriers. Carriers managed by one MAC layer are not necessarilycontiguous to each other. When one MAC layer manages and operates theplurality of carriers, there is an advantage in that resource managementis flexible.

When the multiple-carrier system uses a time division duplex (TDD)scheme, DL transmission and UL transmission can be included in eachcarrier. When the multiple-carrier system uses a frequency divisionduplex (FDD) scheme, carriers can be used by being divided into a DLcarrier and a UL carrier. In this case, a plurality of DL carriers and aplurality of UL carriers can be supported. A BS may allocate one or moreDL carriers or one or more UL carriers to a UE. In the multiple-carriersystem, the BS may transmit information to one UE simultaneously throughone or more carriers. The UE also may transmit information to the BSsimultaneously through one or more carriers.

The multiple-carrier system can be classified into a symmetricalstructure and an asymmetrical structure. The symmetrical structure is acase where the number of DL carriers is equal to the number of ULcarriers. The asymmetrical structure is a case where the number of DLcarriers is different from the number of UL carriers. A case where abandwidth of the DL carrier is different from a bandwidth of a ULcarrier can also be considered as the asymmetrical structure.

FIG. 10 is a block diagram showing an exemplary structure of aninformation processor included in a transmitter.

Referring to FIG. 10, an information processor 110 includes a channelcoding unit 111, a modulator 112, and an information sequence generator113.

An information bit corresponding to information to be transmitted by thetransmitter is input to the channel coding unit 111. The channel codingunit 111 performs channel coding on the information bit to generate anencoded bit. There is no restriction on a channel coding scheme.Examples of the channel coding scheme include turbo coding, convolutioncoding, block coding, etc. The block code may be a Reed-Muller codefamily. A size of the encoded bit output from the channel coding unit111 may be various.

The channel coding unit 111 may perform rate matching on the encoded bitto generate a rate-matched bit. Hereinafter, the encoded bit mayrepresent the rate-matched bit.

The modulator 112 maps the encoded bit to a symbol that expresses aposition on a signal constellation to generate a modulation symbol.There is no restriction on a modulation scheme. Examples of themodulation scheme include m-phase shift keying (m-PSK), m-quadratureamplitude modulation (m-QAM), etc. One or a plurality of modulationsymbols can be provided. The number of modulation symbols may be variousaccording to the size of the encoded bit input to the modulator 112 andthe modulation scheme.

The information processor 110 may (or may not) perform discrete Fouriertransform (DFT) on the modulation symbol. In 3GPP LTE, DFT is notperformed when information is transmitted through a PUCCH, and isperformed when information is transmitted through a PUSCH. Whenperforming DFT, the information processor 110 may further include a DFTunit (not shown) for outputting a complex-valued symbol by performingDFT on the modulation symbol. It is assumed herein that a modulationsymbol on which DFT is not performed is input to the informationsequence generator 113.

The information sequence generator 113 generates an information sequencebased on an information symbol or sequence. Hereinafter, one or aplurality of complex-valued symbols input to the information sequencegenerator 113 is collectively referred to as the information symbol. Theinformation symbol represents one or a plurality of normalcomplex-valued symbols corresponding to information to be transmitted bythe information processor 110. For example, the information symbol maybe a modulation symbol, a complex-valued symbol on which DFT isperformed on the modulation symbol, any signal, a complex-valued signal,a spread symbol obtained after spreading the modulation symbol, or thelike. The information sequence may be a one-dimensional spread sequenceor a two-dimensional spread sequence.

(1) One-Dimensional Spread Sequence

The one-dimensional spread sequence is generated based on a modulationsymbol and a 1^(st) sequence. One modulation symbol or each of aplurality of modulation symbols may be multiplied by the 1^(st) sequenceto generate the one-dimensional spread sequence.

Equation 3 below shows an example of generating K one-dimensional spreadsequences s(n) based on modulation symbols d(0), . . . , d(K−1) and a1^(st) sequence x(n) with a length N (K and N are natural numbers, and nis an element index of the 1^(st) sequence, where 0≦n≦N−1).

s(n)d(k)x(n),0≦k≦K−1  

Equation 3

In Equation 3, the modulation symbols d(0), . . . , d(K−1) may be Kmodulation symbols. Alternatively, one modulation symbol d(0) may berepetitively used K times.

The one-dimensional spread sequence s(n) is mapped to a time domain or afrequency domain. When it is mapped to the time domain, theone-dimensional spread sequence s(n) may be mapped to time samples,chips, or OFDM symbols. When it is mapped to the frequency domain, theone-dimensional spread sequence s(n) may be mapped to subcarriers.

Hereinafter, when the one-dimensional spread sequence s(n) is mapped tothe time domain, the 1^(st) sequence x(n) is called a time-domainsequence. When the one-dimensional spread sequence s(n) is mapped to thefrequency domain, the 1^(st) sequence x(n) is called a frequency-domainsequence.

(2) Two-Dimensional Spread Sequence

The two-dimensional spread sequence is generated based on theone-dimensional spread sequence and a 2^(nd) sequence. That is, thetwo-dimensional spread sequence is generated based on the modulationsymbol, the 1^(st) sequence, and the 2^(nd) sequence. Theone-dimensional spread sequence may be spread to the 2^(nd) sequence togenerate the two-dimensional spread sequence.

Equation 4 below shows an example of generating a two-dimensional spreadsequence z(n,k) by spreading K one-dimensional spread sequences s(n) toa 2^(nd) sequence y(k) (k is an element index of the 2^(nd) sequence,where 0≦k≦K−1).

z(n,k)=w(k)y(n)=w(k)d(k)x(n)  

Equation 4

The two-dimensional spread sequence z(n,k) is mapped to the time domainor the frequency domain. For example, n may correspond to a subcarrierindex, and k may correspond to a symbol index. Alternatively, n maycorrespond to a symbol index, and k may correspond to a subcarrierindex.

An RS sequence may be generated similarly to generation of aninformation sequence. When the information sequence is theone-dimensional spread sequence, the 1^(st) sequence for an RS may beused as the RS sequence. If the information sequence is thetwo-dimensional spread sequence, the RS sequence may be generated basedon the 1^(st) sequence for the RS and the 2^(nd) sequence for the RS.

As such, to perform information transmission, the transmitter 100 has todetermine a resource used for information transmission. The resource mayconsist of at least one of (1) the 1^(st) sequence, (2) the 2^(nd)sequence, and (3) resource blocks. For example, the 1^(st) sequence maybe a cyclic shifted sequence, and the 2^(nd) sequence may be anorthogonal sequence.

A resource index identifies the resource used for informationtransmission. Therefore, the resource is determined from the resourceindex. Each of sequences used to generate the information sequence andthe RS sequence is determined from the resource index. In addition, aresource block to which the information sequence and the RS sequence aremapped can be determined from the resource index.

Therefore, the transmitter 100 has to obtain the resource index toperform information transmission. When the transmitter is a part of aBS, the transmitter may determine the resource index through scheduling.

When the transmitter is a part of a UE, a method of obtaining theresource index of the UE is problematic. The BS may report the resourceindex to the UE explicitly or implicitly. In addition, the resourceindex may change semi-statically or dynamically.

For example, the resource index may be determined by higher layersignaling. The higher layer may be an RRC layer. In this case, theresource index changes semi-statically. Information to be transmitted bythe UE may be SR, semi-persistent scheduling (SPS) ACK/NACK, CQI, etc.The SPS ACK/NACK is HARQ ACK/NACK for DL data transmitted throughsemi-static scheduling. When the DL data is transmitted through a PDSCH,a PDCCH corresponding to the PDSCH may not exist.

For another example, the UE may obtain the resource index from a radioresource by which a control channel for receiving the DL data istransmitted. In this case, information transmitted by the UE may bedynamic ACK/NACK. The dynamic ACK/NACK is ACK/NACK for DL datatransmitted through dynamic scheduling. In the dynamic scheduling, theBS transmits a DL grant to the UE every time through a PDCCH whenever DLdata is transmitted through the PDSCH.

Equation 5 below shows an example of determining a resource index R fordynamic ACK/NACK transmission.

R=n(CCE)+N(PUCCH)  

Equation 5

In Equation 5, n(CCE) denotes a 1^(st) CCE index used for PDCCHtransmission with respect to a PDSCH, and N(PUCCH) denotes the number ofresource indices allocated for SR and SPS ACK/NACK. N(PUCCH) is acell-specific parameter, and can be determined by a higher layer such asan RRC layer.

Therefore, the BS can regulate a resource for ACK/NACK transmission bycontrolling the 1^(st) CCE index used for PDCCH transmission.

As an example of an information transmission method based on CDM andFDM, there is a method transmitting UL control information through aPUCCH. Hereinafter, the method of transmitting the UL controlinformation through the PUCCH will be described.

The PUCCH can support multiple formats. That is, it is possible totransmit the UL control signal whose number of bits per subframe differsaccording to the modulation scheme. Table 5 below shows an example of amodulation scheme and the number of bits per subframe based on a PUCCHformat.

TABLE 5 PUCCH Modulation Number of bits per format scheme subframe 1 N/AN/A 1a BPSK 1 1b QPSK 2 2 QPSK 20 2a QPSK + BPSK 21 2b QPSK + QPSK 22

The PUCCH format 1 is used to transmit the SR. The PUCCH format 1a/1b isused to transmit the HARQ ACK/NACK signal. The PUCCH format 2 is used totransmit the CQI. The PUCCH format 2a/2b is used to transmit the CQI andthe HARQ ACK/NACK signal.

In any subframe, if the HARQ ACK/NACK signal is transmitted alone, thePUCCH format 1a/1b is used, and if the SR is transmitted alone, thePUCCH format 1 is used. The UE can transmit the HARQ ACK/NACK signal andthe SR simultaneously in the same subframe. For positive SRtransmission, the UE transmits the HARQ ACK/NACK signal by using a PUCCHallocated for the SR. For negative SR transmission, the UE transmits theHARQ ACK/NACK signal by using a PUCCH resource allocated for theACK/NACK.

In case of the PUCCH format 1a, an ACK/NACK bit (one bit) is output froma channel coding unit. For example, each ACK may be coded to a binary1′, and each NACK may be coded to a binary ‘0’. In case of the PUCCHformat 1b, ACK/NACK bits (two bits) b(0) and b(1) may be output from thechannel coding unit. b(0) may correspond to an ACK/NACK bit for a 1^(st)codeword, and b(1) may correspond to an ACK/NACK bit for a 2^(nd)codeword. That is, the PUCCH format 1a is for HARQ ACK/NACK informationfor the 1^(st) codeword, and the PUCCH format 1b is for HARQ ACK/NACKinformation of the 2^(nd) codeword.

Each of the PUCCH formats 1, 1a, and 1b uses one complex-valued symbold(0). The BS can detect an SR by only determining whether there is PUCCHformat 1 transmission from the UE. That is, an on-off keying (OOK)modulation scheme can be used in SR transmission. Therefore, any complexvalue can be used as a value of the modulation symbol d(0) for the PUCCHformat 1. For example, d(0)=1 may be used. The modulation symbol d(0)for the PUCCH format 1a is a modulation symbol generated when an encodedbit (1 bit) is modulated by using binary phase shift keying (BPSK). Thecomplex-valued symbol d(0) for the PUCCH format 1b is a modulationsymbol generated when encoded bits (2 bits) are modulated by usingquadrature phase shift keying (QPSK).

Table 6 below shows an example of a modulation symbol to which anACK/NACK bit is mapped according to a modulation scheme.

TABLE 6 Modulation scheme Bit(s) d(0) BPSK 0  1 1 −1 QPSK 00  1 01 −j 10 j 11 −1

FIG. 11 shows an example of PUCCH format 1/1a/1b transmission in case ofa normal CP. Although it is expressed herein that resource blocksbelonging to a resource block pair occupy the same frequency band in a1^(st) slot and a 2^(nd) slot, the resource blocks can be hopped in aslot level as described with reference to FIG. 7.

Referring to FIG. 11, the 1^(st) slot and the 2^(nd) slot each include 7OFDM symbols. Among the 7 OFDM symbols included in each slot, 3 OFDMsymbols correspond to an RS part to which an RS sequence is mapped, andthe remaining 4 OFDM symbols correspond to an information part to whichan information sequence is mapped. The RS part corresponds to 3contiguous OFDM symbols located in the middle of each slot. The positionand number of OFDM symbols used as the RS part in each slot may vary,and thus the position and number of OFDM symbols used as the informationpart may also vary.

In the information part, an information sequence is generated based on amodulation symbol d(0), a cyclically shifted sequence r(n,Ics), and anorthogonal sequence w(k, Ios). The cyclically shifted sequence r(n,Ics)may also be referred to as a 1^(st) sequence, and the orthogonalsequence w(k, Ios) may also be referred to as a 2^(nd) sequence.Therefore, the information sequence is a two-dimensional spreadsequence. By spreading information to a time-space domain, UEmultiplexing capacity can be increased. The UE multiplexing capacity isthe number of UEs that can be multiplexed to the same resource block.

The cyclically shifted sequence r(n,Ics) is generated from a basesequence for each OFDM symbol used as the information part within thesubframe. The base sequence is identical within one slot. The 1^(st)slot and the 2^(nd) slot may have identical or different base sequenceswithin the subframe. The cyclically shifted index Ics is determined froma resource index. The cyclically shifted index Ics can be CS-hopped in asymbol level. Hereinafter, hopping of a CS index in the symbol level iscalled CS hopping. The CS hopping can be performed according to a slotnumber n(s) within a radio frame and a symbol index 1 within a slot.Therefore, the CS index Ics can be expressed by Ics(n(s),l). CS hoppingcan be performed in a cell-specific manner to randomize inter-cellinterference. In FIG. 11, the value Ics for each OFDM symbol in theinformation part is for exemplary purposes only.

A 1^(st) sequence s(n) spread in a frequency domain is generated foreach OFDM symbol of the information part on the basis of the modulationsymbol d(0) and the cyclically shifted sequence r(n,Ics). The 1^(st)sequence s(n) can be generated by multiplying the modulation symbol d(0)by the cyclically shifted sequence r(n,Ics) according to Equation 6below.

s(n)=d(0)r(n,I _(cs))  

Equation 6

An information sequence spread to a time-frequency domain is generatedon the basis of the 1^(st) sequence s(n) generated for each OFDM symbolof the information part and the orthogonal sequence w(k, Ios) having alength of K=4. The 1^(st) sequence may be spread in a block type byusing the orthogonal sequence w(k, Ios) to generate the informationsequence. Elements constituting the orthogonal sequence correspond toOFDM symbols of the information part sequentially in a one-to-onemanner. Each of the elements constituting the orthogonal sequence ismultiplied by the 1st sequence s(0) mapped to its corresponding OFDMsymbol to generate the information sequence.

The information sequence is mapped to a resource block pair allocated toa PUCCH within the subframe. The resource block pair is determined fromthe resource index. After the information sequence is mapped to theresource block pair, IFFT is performed on each OFDM symbol of thesubframe to output a time-domain signal. Although the orthogonalsequence is multiplied before IFFT is performed in this case, the sameresult can also be obtained when the 1^(st) sequence s(n) is mapped tothe resource block pair and thereafter the orthogonal sequence ismultiplied.

When a sounding reference signal (SRS) and the PUCCH formats 1/1a/1b areconcurrently transmitted in one subframe, one OFDM symbol on the PUCCHis punctured. For example, a last OFDM symbol of the subframe may bepunctured. In this case, in the 1^(st) slot of the subframe, the controlinformation consists of 4 OFDM symbols. In the 2^(nd) slot of thesubframe, the control information consists of 3 OFDM symbols. Therefore,the orthogonal sequence having the spreading factor K=4 is used for the1^(st) slot, and the orthogonal sequence having the spreading factor K=3is used for the 2^(nd) slot.

An orthogonal sequence Ios is determined from the resource index. Theorthogonal sequence index Ios may be hopped in a slot level.Hereinafter, hopping of the orthogonal sequence index in the slot levelis referred to as orthogonal sequence (OS) remapping. The OS remappingcan be performed according to the slot number n_(s) within the radioframe. Therefore, the orthogonal sequence index Ios can be expressed byIos(n_(s)). The OS remapping may be performed to randomize inter-cellinterference.

In the RS part, the RS sequence is generated on the basis of thecyclically shifted sequence r(n,I′cs) and the orthogonal sequence w(k,I′os) having a length of K=3. I′cs denotes a CS index for the RS, andI′os denotes an orthogonal sequence index for the RS. I′cs and I′os aredetermined from respective resource indices. A cyclically shiftedsequence is a frequency-domain sequence, and an orthogonal sequence is atime-domain sequence. Therefore, the RS sequence is a sequence which isspread to a time-frequency domain similarly to the information sequence.

In the RS part, the base sequence for generating the cyclically shiftedsequence may be identical to the base sequence of the information part.The CS index Ics of the information part and the CS index I′cs of the RSpart are both determined from the resource index. However, a method ofdetermining the CS index from the resource index may be identical ordifferent between the information part and the RS part.

FIG. 12 shows an example of PUCCH format 1/1a/1b transmission in case ofan extended CP. Although it is expressed herein that resource blocksbelonging to a resource block pair occupy the same frequency band in a1^(st) slot and a 2^(nd) slot, the resource blocks can be hopped in aslot level as described with reference to FIG. 7.

Referring to FIG. 12, the 1^(st) slot and the 2^(nd) slot each include 6OFDM symbols. Among the 6 OFDM symbols included in each slot, 2 OFDMsymbols correspond to an RS part, and the remaining 4 OFDM symbolscorrespond to an information part. Other than that, the example of FIG.11 in which the normal CP is used is applied directly. However, in theRS part, an RS sequence is generated on the basis of the cyclicallyshifted sequence and an orthogonal sequence having a length of K=2.

As described above, in both cases of the normal CP and the extended CP,a resource used for PUCCH format 1/1a/1b transmission has to beidentified by a resource index. A resource block for transmittinginformation, a CS index Ics and an orthogonal sequence index Ios forgeneration of an information sequence, and a CS index I′cs and anorthogonal sequence index I′os for generation of the RS sequence aredetermined from the resource index.

For example, when a CS interval is 2 in the extended CP, the UEmultiplexing capacity is as follows. Since the number of CS indices Icsand the number of orthogonal sequence indices Ios for the controlinformation are respectively 6 and 3, 18 UEs can be multiplexed per oneRB. However, the number of CS indices I′cs and the number of orthogonalsequence indices I′os for generation of the RS sequence are respectively6 and 2, 12 UEs can be multiplexed per one resource block. Therefore,the UE multiplexing capacity is limited by the RS part rather than theinformation part.

FIG. 13 shows an example of PUCCH format 2 transmission when a normal CPis used. Although it is shown herein that resource blocks belonging to aresource block pair occupy the same frequency band in a 1^(st) slot anda 2^(nd) slot, the resource blocks may be hopped in a slot level asdescribed in FIG. 7.

Referring to FIG. 13, among the 7 OFDM symbols included in each slot, 2OFDM symbols correspond to an RS part to which an RS sequence is mapped,and the remaining 5 OFDM symbols correspond to an information part towhich an information sequence is mapped. The position and number of OFDMsymbols used as the RS part in each slot may vary, and thus the positionand number of OFDM symbols used as the information part may also vary.

A UE generates an encoded CQI bit by performing channel coding on a CQIinformation bit. In this case, a block code may be used. In 3GPP LTE, ablock code (20, A) is used, where A is a size of the CQI informationbit. That is, in the 3GPP LTE, encoded bits (20 bits) are generatedalways irrespective of the size of the CQI information bit.

Table 7 below shows an example of 13 basis sequences for the block code(20, A).

TABLE 7 i M(i, 0) M(i, 1) M(i, 2) M(i, 3) M(i, 4) M(i, 5) M(i, 6) M(i,7) M(i, 8) M(i, 9) M(i, 10) M(i, 11) M(i, 12) 0 1 1 0 0 0 0 0 0 0 0 1 10 1 1 1 1 0 0 0 0 0 0 1 1 1 0 2 1 0 0 1 0 0 1 0 1 1 1 1 1 3 1 0 1 1 0 00 0 1 0 1 1 1 4 1 1 1 1 0 0 0 1 0 0 1 1 1 5 1 1 0 0 1 0 1 1 1 0 1 1 1 61 0 1 0 1 0 1 0 1 1 1 1 1 7 1 0 0 1 1 0 0 1 1 0 1 1 1 8 1 1 0 1 1 0 0 10 1 1 1 1 9 1 0 1 1 1 0 1 0 0 1 1 1 1 10 1 0 1 0 0 1 1 1 0 1 1 1 1 11 11 1 0 0 1 1 0 1 0 1 1 1 12 1 0 0 1 0 1 0 1 1 1 1 1 1 13 1 1 0 1 0 1 0 10 1 1 1 1 14 1 0 0 0 1 1 0 1 0 0 1 0 1 15 1 1 0 0 1 1 1 1 0 1 1 0 1 16 11 1 0 1 1 1 0 0 1 0 1 1 17 1 0 0 1 1 1 0 0 1 0 0 1 1 18 1 1 0 1 1 1 1 10 0 0 0 0 19 1 0 0 0 0 1 1 0 0 0 0 0 0

In Table 7, M_(i,n), denotes a basis sequence (where 0≦n≦12, n is aninteger). The encoded bit is generated by linear combination of the 13basis sequences. Equation 7 below shows an example of the encoded bitb_(i) (0≦i≦19, where i is an integer).

$\begin{matrix}{{b(i)} = {\sum\limits_{n = 0}^{A - 1}{\left\{ {{a(n)} \cdot {M\left( {i,n} \right)}} \right\} {{mod}2}}}} & \left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack\end{matrix}$

In Equation 7, a₀, a₁, . . . , a_(A-1) denotes an information bit, and Adenotes the size of the information bit (where A is a natural number).

The encoded bits (20 bits) are mapped to 10 modulation symbols d(0), . .. , d(9) by using QPSK modulation. In the PUCCH format 2a, 1-bit HARQACK/NACK information is mapped to one modulation symbol d(10) by usingBPSK modulation. In the PUCCH format 2b, 2-bit HARQ ACK/NACK informationis mapped to one modulation symbol d(10) by using QPSK modulation. Thatis, in the PUCCH format 2a, the CQI and the 1-bit HARQ ACK/NACKinformation are concurrently transmitted, and in the PUCCH format 2b,the CQI and the 2-bit HARQ ACK/NACK information are concurrentlytransmitted. Herein, d(10) is used for generation of an RS. d(10)corresponds to one OFDM symbol between two OFDM symbols on which the RSis carried in each slot. In other words, according to d(10), phasemodulation is performed on the RS carried on one OFDM symbol in eachslot. The PUCCH formats 2a/2b can be supported only for the normal CP.As such, in each of the PUCCH formats 2a and 2b, one modulation symbolis used for generation of the RS.

In the information part, an information sequence is generated based onmodulation symbols d(0), . . . , d(9) and a cyclically shifted sequencer(n,Ics). Each modulation symbol can be multiplied to the cyclic shiftedsequence r(n,Ics). The information sequence is a one-dimensional spreadsequence. Unlike the PUCCH formats 1/1a/1b, an orthogonal sequence isnot used in the PUCCH formats 2/2a/2b.

The cyclically shifted sequence r(n,Ics) is generated from a basesequence for each OFDM symbol used as the information part within thesubframe. The base sequence is identical within one slot. The 1^(st)slot and the 2^(nd) slot may have identical or different base sequenceswithin the subframe. The cyclically shifted index Ics is determined froma resource index. The cyclically shifted index Ics can be CS-hopped in asymbol level. The CS hopping can be performed according to a slot numbern(s) within a radio frame and a symbol index 1 within a slot. Therefore,the CS index Ics can be expressed by Ics(n(s),l). In FIG. 13, a valueIcs for each OFDM symbol in the information part is for exemplarypurposes only.

In the RS part, the cyclically shifted sequence r(n,I′cs) can be used asthe RS sequence. I′cs is a CS index for the RS. I′cs is determined fromthe resource index.

In the RS part, the base sequence for generating the cyclically shiftedsequence may be identical to the base sequence of the information part.The CS index Ics of the information part and the CS index I′cs of the RSpart are both determined from the resource index. However, a method ofdetermining the CS index from the resource index may be identical ordifferent between the information part and the RS part.

In the PUCCH format 2a/2b, d(10) corresponds to one OFDM symbol of theRS part. That is, an RS sequence in which d(10) and the cyclicallyshifted sequence are multiplied is mapped to one OFDM symbol of the RSpart within each slot.

FIG. 14 shows an example of PUCCH format 2 transmission when an extendedCP is used. Although it is shown herein that resource blocks belongingto a resource block pair occupy the same frequency band in a 1^(st) slotand a 2^(nd) slot, the resource blocks may be hopped in a slot level asdescribed in FIG. 7.

Referring to FIG. 14, each of the 1^(st) slot and the 2^(nd) slotincludes 6 OFDM symbols. Among the 6 OFDM symbols included in each slot,one OFDM symbol corresponds to an RS part, and the remaining 5 OFDMsymbols correspond to an information part. Other than that, the normalCP case of FIG. 13 is applied directly.

As described above, in both cases of the normal CP and the extended CP,a resource used for PUCCH format 2/2a/2b transmission has to beidentified by a resource index. A resource block for transmittinginformation, a CS index Ics for generation of an information sequence,and a CS index I′cs for generation of an RS sequence are determined fromthe resource index. If a CS interval is 1, the number of CS indices Icsis 12 and the number of CS indices I′cs is 12. Thus, 12 UEs can bemultiplexed per one resource block. If the CS interval is 2, the numberof CS indices Ics is 6 and the number of CS indices I′cs is 6. Thus, 6UEs can be multiplexed per one resource block.

As such, information can be transmitted by using code divisionmultiplexing (CDM) and/or frequency division multiplexing (FDM) as amultiplexing scheme. One transmit (Tx) antenna and one resource indexare used in the information transmission method described up to now.However, to increase an amount of information that is transmittedconcurrently, multiple resources can be allocated to a transmitter. Wheninformation is transmitted through multiple Tx antennas or informationis transmitted through multiple carriers, the multiple resources can beallocated. Therefore, there is a need to provide a method forinformation transmission through multiple Tx antennas and a method forinformation transmission through multiple carriers.

Method for Information Transmission Through Multiple Antennas

FIG. 15 is a block diagram showing an exemplary structure of atransmitter including two antennas. Herein, the transmitter may be apart of a UE or a part of a BS.

Referring to FIG. 15, a transmitter 200 includes an informationprocessor 210, a reference signal generator 220, 1^(st) and 2^(nd)resource block mappers 230-1 and 230-2, 1^(st) and 2^(nd) OFDM signalgenerators 240-1 and 240-2, 1^(st) and 2^(nd) RF units 250-1 and 250-2,and two antennas 290-1 and 290-2.

The 1^(st) and 2^(nd) resource block mappers 230-1 and 230-2 arerespectively coupled to the 1^(st) and 2^(nd) OFDM signal generators240-1 and 240-2. The 1^(st) and 2^(nd) OFDM signal generators 240-1 and240-2 are respectively coupled to the 1^(st) and 2^(nd) RF units 250-1and 250-2. The 1^(st) and 2^(nd) RF units 250-1 and 250-2 arerespectively coupled to the two antennas 290-1 and 290-2. That is, ann^(th) resource block mapper 230-n is coupled to an n^(th) OFDM symbolgenerator 240-n, the n^(th) OFDM signal generator 240-n is coupled to ann^(th) RF unit 250-n, and the n^(th) RF unit is coupled to an n^(th)antenna 290-n. In case of multiple-antenna transmission, there may beone resource grid defined for each antenna.

Two resource indices are allocated to the transmitter 200. Theinformation processor 210 generates information sequences based on thetwo resource indices. Other than that, the description on theinformation transmission method of FIG. 8 to FIG. 14 can also be appliedto a method and apparatus for information transmission through aplurality of Tx antennas.

Hereinafter, a method of generating information sequences based on tworesource indices in the information processor 210 will be described.

FIG. 16 is a block diagram showing an exemplary structure of a part of atransmitter including two antennas.

Referring to FIG. 16, the information processor 210 includes a channelcoding unit 211, a modulator 212, and 1^(st) and 2^(nd) informationsequence generators 213-1 and 213-2. The 1^(st) information sequencegenerator 213-1 is coupled to a 1^(st) resource block mapper 230-1, andthe 2^(nd) information sequence generator 213-2 is coupled to a 2^(nd)resource block mapper 230-2.

The information processor 210 can generate information sequences byusing orthogonal space resource transmit diversity (OSRTD) or orthogonalspace resource spatial multiplexing (OSRSM).

1. OSRTD

It is assumed that s(1) is an information symbol corresponding toinformation to be transmitted by the transmitter 200. Herein, theinformation symbol may be any signal, a complex-valued signal, one ormore modulation symbols, or a spread sequence.

The modulator 212 outputs s(1). Then, s(1) is input to each of the1^(st) information sequence generator 213-1 and the 2^(nd) informationsequence generator 213-2.

The 1^(st) information sequence generator 213-1 generates a 1^(st)information sequence based on s(1) and a 1^(st) resource index. The2^(nd) information sequence generator 213-2 generates a 2^(nd)information sequence based on s(1) and a 2^(nd) resource index. The1^(st) information sequence is transmitted through the 1^(st) antenna290-1, and the 2^(nd) information sequence is transmitted through the2^(nd) antenna 290-2. When the 1^(st) resource index and the 2^(nd)resource index are allocated differently, orthogonality can bemaintained between antennas.

In order to perform channel estimation for each antenna, an RS has to begenerated for each antenna. For this, each resource index may be mappedto each antenna in a one-to-one manner. Therefore, an RS for the 1^(st)antenna may be generated based on the 1^(st) resource index, and an RSfor the 2^(nd) antenna may be generated based on the 2^(nd) resourceindex.

As such, the OSRTD is a method in which a resource index is allocatedfor each antenna and the same information is repetitively transmitted inan orthogonal manner for each antenna. By repetitively transmitting thesame information through a plurality of antennas, a diversity gain canbe obtained, and reliability of wireless communication can be increased.

If it is assumed that 18 UEs can be multiplexed per one resource blockin case of single-antenna transmission, 9 UEs can be multiplexed per oneresource block when using OSRTD for two antennas. In case of the PUCCHformat 1/1a/1b, the same information is transmitted in a 1^(st) slot anda 2^(nd) slot. A resource block allocated to the PUCCH is hopped in aslot level. That is, by transmitting information through differentsubcarriers over time, a frequency diversity gain can be obtained.However, if a sufficient diversity gain can be obtained by using theOSRTD, the same control information as that of the 1^(st) slot is notnecessarily transmitted in the 1^(st) slot. Therefore, differentinformation can be transmitted in the 1^(st) slot and the 2^(nd) slot.In this case, UE multiplexing capacity of the OSRTD for the two antennasmay be maintained to be the same as UE multiplexing capacity ofsingle-antenna transmission. For example, in case of the single-antennatransmission, if 18 UEs are multiplexed per one resource block, 18 UEscan also be multiplexed per one resource block even in the OSRTD for thetwo antennas.

The 2^(nd) information sequence generator 213-2 may generate the 2^(nd)information sequence by modifying the information symbol s(1). Forexample, the 2^(nd) information sequence can be generated based on s(1)*and the 2^(nd) resource index. Herein, (·)* denotes a complex conjugate.Alternately, a modified information symbol s(2) processed by the 2^(nd)information sequence generator can be expressed by Equation 8 below.

s(2)=s(1)·exp(jθ) or a·s(1)  

Equation 8

In Equation 8, ‘a’ denotes a complex-valued scaling factor of the 2^(nd)information sequence generator.

A Tx signal matrix can be expressed by Equation 9 below.

$\begin{matrix}\begin{bmatrix}{s(1)} & 0 \\0 & {s(1)}\end{bmatrix} & \left\lbrack {{Equation}\mspace{14mu} 9} \right\rbrack\end{matrix}$

In Equation 9, a row and/or column of the Tx signal matrix maycorrespond to a Tx antenna, a resource index, etc. For example, rows ofthe Tx signal matrix may correspond to respective resource indices, andcolumns thereof may correspond to respective Tx antennas.

y(1) denotes a 1^(st) Rx signal for the 1^(st) information sequencegenerated based on the 1^(st) resource index. y(2) denotes a 2^(nd) Rxsignal for the 2^(nd) information sequence generated based on the 2^(nd)resource index. An actual Rx signal y is a combination of the 1^(st) Rxsignal y1 and the 2^(nd) Rx signal y2, i.e., y=y(1)+y(2). However, it isassumed that the Rx signal y can be split into the 1^(st) Rx signal y1and the 2^(nd) Rx signal y2 by using a de-spreading operation. Forconvenience of explanation, it is assumed that a receiver has one Rxantenna.

An Rx signal matrix can be expressed by Equation 10 below.

$\begin{matrix}{\begin{bmatrix}{y(1)} \\{y(2)}\end{bmatrix} = {{\begin{bmatrix}{s(1)} & 0 \\0 & {s(1)}\end{bmatrix}\begin{bmatrix}{h(1)} \\{h(2)}\end{bmatrix}} + \begin{bmatrix}{n(1)} \\{n(2)}\end{bmatrix}}} & \left\lbrack {{Equation}\mspace{14mu} 10} \right\rbrack\end{matrix}$

In Equation 10, h(1) denotes a channel for the 1^(st) antenna 290-1,h(2) denotes a channel for the 2^(nd) antenna 290-1, n(1) denotes noiseof the 1^(st) Rx signal, and n(2) denotes noise of the 2^(nd) Rx signal.Herein, the noise may be additive white Gaussian noise (AWGN).

In general, if Tx power is limited, a normalization factor correspondingto the number of Tx antennas can be used. Equation 11 below shows anexample of the normalization factor.

$\begin{matrix}\frac{1}{\sqrt{{Ntx}{Nc}}} & \left\lbrack {{Equation}\mspace{14mu} 11} \right\rbrack\end{matrix}$

In Equation 11, Ntx denotes the number of Tx antennas, and Nc denotesthe number of resources per antenna. However, for convenience ofexplanation, the normalization factor is omitted in the followingdescription.

When de-spreading is performed on each resource index from the Rxsignal, a diversity gain can be obtained as expressed by Equation 12below.

|h(1)|² |h(2)|²  

Equation 12

The diversity gain is similar to maximal ratio coding (MRC) which isoptimal combining. The MRC scheme is one of signal combining schemes forestimating a Tx signal from an Rx signal received through a plurality ofRx antennas.

Although it is described herein that the number of Tx antennas is 2 forconvenience of explanation, the number of Tx antennas is not limitedthereto.

When the transmitter includes M antennas (where M is a natural number),M resource indices can be allocated. The M antennas can be one-to-onemapped to the M resource indices, respectively. If the number of Txantennas is 3 or more, OSRTD can be used in combination with other Txdiversity schemes such as cyclic delay diversity (CDD) or precodingvector switching (PVS). For example, when using 4 Tx antennas, the 4Txantennas can be divided by two, and thus can be grouped into two antennagroups. The OSRTD is applied to each of the two antenna groups, and theCDD or the PVS can be applied between the groups.

2. OSRSM

It is assumed that s(1) and s(2) are symbols corresponding toinformation to be transmitted by the transmitter 200. In this case, s(1)and s(2) may be symbols obtained after performing joint coding oninformation bits.

The 1^(st) information sequence generator 213-1 generates the 1^(st)information sequence based on the 1^(st) information symbols s(1) andthe 1^(st) resource index. The 2^(nd) information sequence generator213-2 generates the 2^(nd) information sequence based on the 2^(nd)information symbol s(2) and the 2^(nd) resource index. The 1^(st)information sequence is transmitted through the 1^(st) antenna 290-1,and the 2^(nd) information sequence is transmitted through the 2^(nd)antenna 290-2. When the 1^(st) resource index and the 2^(nd) resourceindex are allocated differently, orthogonality can be maintained betweenantennas.

In order to perform channel estimation for each antenna, an RS has to begenerated for each antenna. For this, each resource index may be mappedto each antenna in a one-to-one manner. Therefore, an RS for the 1^(st)antenna may be generated based on the 1^(st) resource index, and an RSfor the 2^(nd) antenna may be generated based on the 2^(nd) resourceindex.

Although it is described herein that the number of Tx antennas is 2 forconvenience of explanation, the number of Tx antennas is not limitedthereto.

When the transmitter includes M antennas (where M is a natural number),the transmitter can transmit M symbols. M resource indices can beallocated to the transmitter. The M antennas can be one-to-one mapped tothe M resource indices, respectively. Different symbols can betransmitted through the respective M antennas. As such, an informationtransmission method having a spatial multiplexing rate of M is calledOSRSM.

The encoded bit which is bit-level information output from the channelcoding unit 211 can be permutated before being modulated by themodulator 212.

It is assumed that 1^(st) encoded bits (2 bits) a(0) and a(1) and 2^(nd)encoded bits (2 bits) b(0) and b(1) are input to the modulator 212. Forexample, the 1^(st) encoded bit may be bit-level information of 1^(st)ACK/NACK for 1^(st) data transmitted through a 1^(st) DL carrier, andthe 2^(nd) encoded bit may be bit-level information of 2^(nd) ACK/NACKfor 2^(nd) data transmitted through a 2^(nd) DL carrier.

The modulator 212 may generate a 1^(st) modulation symbol d(0) byperforming QPSK modulation on the 1^(st) encoded bit, and may generate a2^(nd) modulation symbol e(0) by performing QPSK modulation on the2^(nd) encoded bit.

Alternatively, the modulator 212 may replace the 1^(st) encoded bit andthe 2^(nd) encoded bit and then modulate the bits after replacement. Forexample, the modulator 212 may replace the bits by swapping the 1^(st)bits a(0) and b(0) of the 1^(st) and 2^(nd) encoded bits. The modulatormay generate the 1^(st) modulation symbol d(0) by modulating the bitsb(0) and a(1), and may generate the 2^(nd) modulation symbol e(0) bymodulating the bits a(0) and b(1).

The modulation symbols output from the modulator 212 are input to asplitter (not shown). The splitter splits the modulation symbol into the1^(st) information symbol s(1) and the 2^(nd) information symbol s(2) byusing the 1^(st) modulation symbol d(0) and the 2^(nd) modulation symbole(0). For one example, the 1^(st) modulation symbol may correspond tothe 1^(st) information symbol, and the 2^(nd) modulation symbol maycorrespond to the 2^(nd) information symbol. For another example, the1^(st) modulation symbol and the 2^(nd) modulation symbol may bereplaced and/or mixed and then may be split into the 1^(st) informationsymbol and the 2^(nd) information symbol.

Equation 13 below shows examples of the 1^(st) modulation symbol d(0)and the 2^(nd) modulation symbol e(0) which are replaced and/or mixedand then are split into the 1^(st) information symbol s(1) and the2^(nd) information symbol s(2).

s(1)=d(0)+e(0),s(2)=d(0)−e(0)

s(1)=d(0)−e(0)*,s(2)=e(0)+d(0)*  

Equation 13

Alternatively, as expressed by Equation 14 below, the 1^(st) modulationsymbol d(0) and the 2^(nd) modulation symbol e(0) may be rotated by anyphase, be replaced and/or mixed, and then be split into the 1^(st)information symbol s(1) and the 2^(nd) information symbol s(2).

s(1)=d(0)+e(0)e ^(ja) ,s(2)=d(0)−e(0)e ^(jb)

s(1)=d(0)−e(0)*e ^(ja) ,s(2)=e(0)+d(0)*e ^(jb)  

Equation

In Equation 14, ‘a’ and ‘b’ may be identical or different from eachother.

FIG. 17 is a block diagram showing another exemplary structure of a partof a transmitter including two antennas.

Referring to FIG. 17, an information processor 210 includes a channelcoding unit 211, a modulator 212, and a space-code block code (SCBC)processor 214. The SCBC processor 214 is coupled to 1^(st) and 2^(nd)resource mappers 230-1 and 230-2.

It is assumed that a 1^(st) information symbol s(1) and a 2^(nd)information symbol s(2) are information symbols corresponding toinformation to be transmitted by the transmitter 200.

The SCBC processor 214 generates a 1^(st) Tx symbol and a 4^(th) Txsymbol on the basis of an Alamouti code from the 1^(st) informationsymbol s(1) and the 2^(nd) information symbol s(2).

Hereinafter, a Tx signal matrix is defined as a 2×2 matrix of whichelements are 1^(st) to 4^(th) Tx symbols. An element of an i^(th) rowand j^(th) column of the Tx signal matrix is expressed by (i,j) (wherei=1, 2 and j=1,2). Hereinafter, (1,1) denotes the 1^(st) Tx symbol,(2,1) denotes the 2^(nd) Tx symbol, (1,2) denotes the 3^(rd) Tx symbol,and (2,2) denotes the 4^(th) Tx symbol. The 4^(th) Tx symbols is acomplex conjugate of the 1^(st) Tx symbol, and the 3^(rd) Tx symbol isobtained by appending a minus sign to a complex conjugate of the 2^(nd)Tx symbol. Alternatively, the 4^(th) Tx symbol is obtained by appendinga minus sign to a complex conjugate of the 1^(st) Tx symbol, and the3^(rd) Tx symbols is a complex conjugate of the 2^(nd) Tx symbol.

A Tx signal matrix can be expressed by Equation 15 below.

$\begin{matrix}\begin{bmatrix}{s(1)} & {s(2)} \\{- {s(2)}^{*}} & {s(1)}^{*}\end{bmatrix} & \left\lbrack {{Equation}\mspace{14mu} 15} \right\rbrack\end{matrix}$

In Equation 15, a row and/or column of the Tx signal matrix maycorrespond to a Tx antenna, a resource index, etc. For example, rows ofthe Tx signal matrix may correspond to respective resource indices, andcolumns thereof may correspond to respective Tx antennas.

The Tx signal matrix expressed in Equation 15 above is for exemplarypurposes only, and is not for restricting a format of the Tx signalmatrix. The Tx signal matrix includes all possible unitary transforms ofthe matrix of Equation 15 above. In this case, the unitary transformincludes not only a transform for the 1^(st) information symbol s(1) andthe 2^(nd) information symbol s(2) but also a transform in a state wheres(1) and s(2) are separated into a real part and an imaginary part.

Table 8 below shows various examples of the Tx signal matrix.

TABLE 8 (1) $\begin{bmatrix}s_{1} & s_{2} \\{- s_{2}^{*}} & s_{1}^{*}\end{bmatrix}\quad$ (2) $\begin{bmatrix}s_{1}^{*} & s_{2} \\{- s_{2}^{*}} & s_{1}\end{bmatrix}\quad$ (3) $\begin{bmatrix}s_{1} & s_{2}^{*} \\{- s_{2}} & s_{1}^{*}\end{bmatrix}\quad$ (4) $\begin{bmatrix}s_{1}^{*} & s_{2}^{*} \\{- s_{2}} & s_{1}\end{bmatrix}\quad$ (5) $\begin{bmatrix}s_{1} & {- s_{2}} \\s_{2}^{*} & s_{1}^{*}\end{bmatrix}\quad$ (6) $\begin{bmatrix}s_{1}^{*} & {- s_{2}} \\s_{2}^{*} & s_{1}\end{bmatrix}\quad$ (7) $\begin{bmatrix}s_{1} & {- s_{2}^{*}} \\s_{2} & s_{1}^{*}\end{bmatrix}\quad$ (8) $\begin{bmatrix}s_{1}^{*} & {- s_{2}^{*}} \\s_{2} & s_{1}\end{bmatrix}\quad$

Table 9 below shows another example of the Tx signal matrix.

TABLE 9 (1) $\begin{bmatrix}s_{1} & s_{2} \\s_{2}^{*} & {- s_{1}^{*}}\end{bmatrix}\quad$ (2) $\begin{bmatrix}s_{1}^{*} & s_{2} \\s_{2}^{*} & {- s_{1}}\end{bmatrix}\quad$ (3) $\begin{bmatrix}s_{1} & s_{2}^{*} \\s_{2} & {- s_{1}^{*}}\end{bmatrix}\quad$ (4) $\begin{bmatrix}s_{1}^{*} & s_{2}^{*} \\s_{2} & {- s_{1}}\end{bmatrix}\quad$ (5) $\begin{bmatrix}{- s_{1}} & s_{2} \\s_{2}^{*} & s_{1}^{*}\end{bmatrix}\quad$ (6) $\begin{bmatrix}{- s_{1}^{*}} & s_{2} \\s_{2}^{*} & s_{1}\end{bmatrix}\quad$ (7) $\begin{bmatrix}{- s_{1}} & s_{2}^{*} \\s_{2} & s_{1}^{*}\end{bmatrix}\quad$ (8) $\begin{bmatrix}{- s_{1}^{*}} & s_{2}^{*} \\s_{2} & s_{1}\end{bmatrix}\quad$

The SCBC processor 214 generates 1^(st) to 4^(th) information sequencesas follows, on the basis of the 1^(st) to 4^(th) information symbols andthe 1^(st) and 2^(nd) resource indices.

The 1^(st) information sequence is generated based on the 1^(st) Txsymbol and the 1^(st) resource index.

The 2^(nd) information sequence is generated based on the 2^(nd) Txsymbol and the 2nd resource index.

The 3^(rd) information sequence is generated based on the 3^(rd) Txsymbol and the 3^(rd) resource index.

The 4^(th) information sequence is generated based on the 4^(th) Txsymbol and the 4^(th) resource index.

The SCBC processor 214 inputs the 1^(st) information sequence and the2^(nd) information sequence to the 1^(st) resource block mapper 230-1.The SCBC processor 214 inputs the 3^(rd) information sequence and the4^(th) information sequence to the 2^(nd) resource block mapper 230-2.

Therefore, the 1^(st) information sequence and the 2^(nd) informationsequence may be combined and transmitted through the 1^(st) antenna290-1 (see FIG. 15). The 2^(nd) information sequence and the 4^(th)information sequence may be combined and transmitted through the 2^(nd)antenna 290-1 (see FIG. 15). To decrease a cubic metric (CM), a phase ofat least one information sequence may change when combining oneinformation sequence to another information sequence. Alternatively, aphase of a Tx symbol may change before the information sequence isgenerated. For example, the 2^(nd) information sequence may be combinedwith the 1^(st) information sequence by phase-shifting the 2^(nd)information sequence by a specific phase. In addition, the 4^(th)information sequence may be combined with the 3^(rd) informationsequence by phase-shifting the 4^(th) information sequence by thespecific phase. In case of BPSK, the specific phase may be 90 degrees.In case of QPSK, the specific phase may be 45 degrees.

As such, when CDM/FDM is used as a multiplexing scheme, information canbe transmitted by using a resource according to SCBC. The transmittercan perform smart repetition by using an antenna and a resource, therebybeing able to obtain a diversity gain and to increase reliability ofwireless communication. Hereinafter, such an information transmissionmethod is called an SCBC information transmission method.

In the SCBC information transmission method, a resource index allocatedto an information part is not one-to-one mapped to an antenna. However,an RS has to be generated for each antenna in order to perform channelestimation for each antenna. For this, each resource index can beallowed to be mapped to each antenna in a one-to-one manner. Therefore,an RS for the 1^(st) antenna can be generated based on a 1^(st) resourceindex, and an RS for the 2^(nd) antenna can be generated based on a2^(nd) resource index.

For SCBC information transmission, it is described above that the 2^(nd)resource index is further allocated to the transmitter in addition tothe 1^(st) resource index. However, if different information has alreadybeen allocated by using a different resource index, the 2^(nd) resourceindex is not necessarily allocated additionally.

If it is assumed that 18 UEs can be multiplexed per one resource blockin case of single-antenna transmission, 9 UEs can be multiplexed per oneresource block when using an SCBC transmission method employing twoantennas. In case of the PUCCH format 1/1a/1b, the same information istransmitted in a 1^(st) slot and a 2^(nd) slot. A resource blockallocated to the PUCCH is hopped in a slot level. That is, bytransmitting information through different subcarriers over time, afrequency diversity gain can be obtained. However, if a sufficientdiversity gain can be obtained by using the SCBC transmission method,the same control information as that of the 1^(st) slot is notnecessarily transmitted in the 1^(st) slot. Therefore, differentinformation can be transmitted in the 1^(st) slot and the 2^(nd) slot.In this case, UE multiplexing capacity of the SCBC transmission methodfor the two antennas may be maintained to be the same as UE multiplexingcapacity of single-antenna transmission. For example, in case of thesingle-antenna transmission, if 18 UEs are multiplexed per one resourceblock, 18 UEs can also be multiplexed per one resource block even in theSCBC transmission method for the two antennas.

y(1) denotes a 1^(st) Rx signal for the 1^(st) information sequencegenerated based on the 1^(st) resource index. y(2) denotes a 2^(nd) Rxsignal for the 2^(nd) information sequence generated based on the 2^(nd)resource index. An actual Rx signal y is a combination of the 1^(st) Rxsignal y1 and the 2^(nd) Rx signal y2, i.e., y=y(1)+y(2). However, it isassumed that the Rx signal y can be split into the 1^(st) Rx signal y1and the 2^(nd) Rx signal y2 by using a de-spreading operation. Forconvenience of explanation, it is assumed that a receiver has one Rxantenna.

An Rx signal matrix can be expressed by Equation 16 below.

$\begin{matrix}{\begin{bmatrix}{y(1)} \\{y(2)}\end{bmatrix} = {{\begin{bmatrix}{s(1)} & {s(2)} \\{- {s(2)}^{*}} & {s(1)}^{*}\end{bmatrix}\begin{bmatrix}{h(1)} \\{h(2)}\end{bmatrix}} + \begin{bmatrix}{n(1)} \\{n(2)}\end{bmatrix}}} & \left\lbrack {{Equation}\mspace{14mu} 16} \right\rbrack\end{matrix}$

In Equation 16, h(1) denotes a channel for the 1^(st) antenna 290-1,h(2) denotes a channel for the 2^(nd) antenna 290-1, n(1) denotes noiseof the 1^(st) Rx signal, and n(2) denotes noise of the 2^(nd) Rx signal.Herein, the noise may be AWGN.

In general, if Tx power is limited, a normalization factor correspondingto the number of Tx antennas can be used. For convenience ofexplanation, the normalization factor is omitted in the followingdescription.

Equation 16 above can be equivalently expressed by Equation 17 below.

$\begin{matrix}{\begin{bmatrix}{y(1)} \\{y(2)}^{*}\end{bmatrix} = {{\begin{bmatrix}{h(1)} & {h(2)} \\{h(2)}^{*} & {- {h(1)}^{*}}\end{bmatrix}\begin{bmatrix}{s(1)} \\{s(2)}\end{bmatrix}} + \begin{bmatrix}{n(1)} \\{n(2)}^{*}\end{bmatrix}}} & \left\lbrack {{Equation}\mspace{14mu} 17} \right\rbrack\end{matrix}$

Equation 17 above can be modified to Equation 18 below.

             [Equation  18] $\begin{matrix}{{\begin{bmatrix}{h(1)} & {h(2)} \\{h(2)}^{*} & {- {h(1)}^{*}}\end{bmatrix}^{H}\begin{bmatrix}{y(1)} \\{y(2)}^{*}\end{bmatrix}} = {{{\begin{bmatrix}{h(1)} & {h(2)} \\{h(2)}^{*} & {- {h(1)}^{*}}\end{bmatrix}^{H}\begin{bmatrix}{h(1)} & {h(2)} \\{h(2)}^{*} & {- {h(1)}^{*}}\end{bmatrix}}\begin{bmatrix}{s(1)} \\{s(2)}\end{bmatrix}} +}} \\{{\begin{bmatrix}{h(1)} & {h(2)} \\{h(2)}^{*} & {- {h(1)}^{*}}\end{bmatrix}^{H}\begin{bmatrix}{n(1)} \\{n(2)}^{*}\end{bmatrix}}} \\{= {{\begin{bmatrix}{{{h(1)}}^{2} + {{h(2)}}^{2}} & 0 \\0 & {{{h(1)}}^{2} + {{h(2)}}^{2}}\end{bmatrix}\begin{bmatrix}{s(1)} \\{s(2)}\end{bmatrix}} +}} \\{\begin{bmatrix}{n^{\prime}(1)} \\{n^{\prime}(2)}\end{bmatrix}}\end{matrix}$

In Equation 18, (·)^(H) denotes a Hermitian matrix. The 1^(st) symbol s₁and the 2^(nd) symbol s₂ are orthogonally separated. The receiver canobtain a diversity gain expressed by Equation 12. This is the samediversity gain as the MRC which is the optimal combination.

Although it is described herein that the number of Tx antennas is 2 forconvenience of explanation, the number of Tx antennas is not limitedthereto.

When the transmitter includes M antennas (where M is a natural number),M resource indices can be allocated. The M antennas can be one-to-onemapped to the M resource indices, respectively. If the number of Txantennas is 3 or more, the SCBC information transmission method can beused in combination with other Tx diversity schemes such as cyclic delaydiversity (CDD) or precoding vector switching (PVS). For example, whenusing 4 Tx antennas, the 4Tx antennas can be divided by two, and thuscan be grouped into two antenna groups. The SCBC informationtransmission method is applied to each of the two antenna groups, andthe CDD or the PVS can be applied between the groups.

FIG. 18 is a flowchart showing an example of a method for informationtransmission through two antennas in a transmitter according to anembodiment of the present invention.

Referring to FIG. 18, the transmitter acquires a 1^(st) resource indexand a 2^(nd) resource index (step S110). The transmitter generatesinformation sequences based on the 1^(st) resource index and the 2^(nd)resource index (step S120). The aforementioned OSRTD, OSRSM, SCBC, etc.,can be used as a method of generating the information sequences. Thetransmitter transmits the information sequences through a 1^(st) antennaand a 2^(nd) antenna (step S130).

Up to now, a method for information transmission through multiple Txantennas has been described when using CDM and/or FDM. To transmit themultiple Tx antennas, the 1^(st) resource index and the 2^(nd) resourceindex have to be allocated to the transmitter. A method of allocatingone resource index has been described above. Hereinafter, a method ofallocating the 2^(nd) resource index as an additional resource index bythe transmitter will be described.

The 2^(nd) resource index may be predetermined with respect to the1^(st) resource index. Alternatively, the 2^(nd) resource index may beexplicitly signaled. Alternatively, the 2^(nd) resource index may beimplicitly mapped according to a specific relationship.

Hereinafter, a method of acquiring the 1^(st) resource index and the2^(nd) resource index by a UE to transmit HARQ ACK/NACK will bedescribed. The method of acquiring resource indices described below isapplicable to all information transmission methods based on CDM/FDM.However, for convenience of explanation, the following description willbe based on a dynamic ACK/NACK transmission method with PUCCH format1a/1b.

In order for the UE to transmit the HARQ ACK/NACK, the UE first receivesDL data from a BS. The 1^(st) resource index can be acquired from aradio resource with respect to a physical control channel for receivingDL data. The 2^(nd) resource index can be acquired from the 1^(st)resource index.

More specifically, the 1^(st) resource index is acquired based on thelowest CCE index (1^(st) CCE index) of a CCE aggregation on which aPDCCH for a PDSCH corresponding to the HARQ ACK/NACK is transmitted (seeEquation 5).

The 2^(nd) resource index can be allocated with a specific offset fromthe 1^(st) resource index. In this case, the offset may be predeterminedor may be specified through signaling. For example, the offset may besignaled through a PDCCH, RRC, or a broadcast channel (BCH).

The method of acquiring the 2^(nd) resource index can be classified asfollows.

1. Implicit Mapping

(1) Method 1-1

If a CCE aggregation level of a PDCCH is greater than or equal to 2, a1^(st) resource index R(1) corresponds to a 1^(st) CCE index of a CCEaggregation used for PDCCH transmission, and a 2^(nd) resource indexR(2) corresponds to a 2^(nd) CCE index of the CCE aggregation (i.e.,R(2)=R(1)+1). In this case, the 2^(nd) resource index is different fromthe 1^(st) resource index by an offset of 1.

If the CCE aggregation level of the PDCCH is 1, the UE operates in asingle-antenna mode. In this case, the UE requires only one resourceindex. The UE can estimate the 1^(st) resource index based on the 1^(st)CCE index. In another method, the 2^(nd) resource index R(2) can beacquired by “R(1) −1”.

In Method 1-1, the 1^(st) resource index and the 2^(nd) resource indexcan be allocated without special signaling.

(2) Method 1-2

Irrespective of the CCE aggregation level, the 1^(st) resource indexcorresponds to the 1^(st) CCE index of the CCE aggregation used forPDCCH transmission, and the 2^(nd) resource index is determined based onthe 1^(st) CCE index and the offset. The 2^(nd) resource index can bespecified by calculating the 1^(st) CCE index and the offset.

The offset may be calculated by performing a simple addition operationor a modulo operation in a full available range after performing theaddition operation. For example, the 2^(nd) resource index R(2) can beacquired by Equation 19 below.

R(2)=R(1)+offset

or R(2)=mod {R(1)+offset,N(range)}  

Equation 19

In Equation 19, R(1) denotes the 1^(st) resource index, and N(range)denotes an available range of the resource index. If the offset is 1, itis the same as the case where the CCE aggregation level is greater thanor equal to 2 in Method 1-1.

In Method 1-2, the 1^(st) resource index and the 2^(nd) resource indexcan be allocated without special signaling.

2. Explicit Mapping

(1) Method 2-1

If the CCE aggregation level of the PDCCH is greater than or equal to 2,the 1^(st) resource index corresponds to the 1^(st) CCE index of the CCEaggregation used for PDCCH transmission, and the 2^(nd) resource indexcorresponds to the 2^(nd) CCE index of the CCE aggregation.

If the CCE aggregation level of the PDCCH is 1, the 1^(st) resourceindex corresponds to the 1^(st) CCE index of the CCE aggregation usedfor PDCCH transmission, and the 2^(nd) resource index may be explicitlyreported by the BS to the UE. As a method of explicitly reporting the2^(nd) resource index, physical layer signaling or higher layer (e.g.,RRC) signaling may be used. For physical layer signaling, the PDCCH mayinclude an information field indicating the 2^(nd) resource index.

Method 2-1 is identical to Method 1-1 if the CCE aggregation level ofthe PDCCH is greater than or equal to 2. If the CCE aggregation level ofthe PDCCH is 1, the 1^(st) resource index corresponds to the 1^(st) CCEindex, and the 2^(nd) resource index may be subjected to PDCCH signalingor RRC signaling.

(2) Method 2-2

Irrespective of the CCE aggregation level, the 1^(st) resource indexcorresponds to the 1^(st) CCE index, and the 2^(nd) resource index issubjected to PDCCH signaling or RRC signaling. In this case, signaledinformation may be an absolute 2^(nd) resource index, or may be anoffset value which is a difference between the 1^(st) resource index andthe 2^(nd) resource index.

Herein, if the offset is 1, the 2^(nd) resource index may be reported byusing 1-bit information. If the 1-bit information is ‘1’, the 2^(nd)resource index is “1^(st) resource index+1”. If the 1-bit information is‘0’, the 2^(nd) resource index becomes equal to the 1^(st) resourceindex, and thus only one resource index can be used. That is, off/of ofthe offset can be specified through the 1-bit information.

FIG. 19 shows an example of a method of multiplexing a plurality ofPDCCHs for a plurality of UEs by a BS.

Referring to FIG. 19, a CCE aggregation constituting a control regionwithin a subframe consists of N(CCE) CCEs indexed from 0 to N(CCE)-1. APDCCH for a UE#1 is transmitted on a CCE aggregation having the CCEindex 0 in a CCE aggregation level 1. A PDCCH for a UE#2 is transmittedon a CCE aggregation having a CCE index 1 in the CCE aggregationlevel 1. A PDCCH for a UE#3 is transmitted on a CCE aggregation havingCCE indices 2 and 3 in a CCE aggregation level 2. A PDCCH for a UE#4 istransmitted on a CCE aggregation having CCE indices 4, 5, 6, and 7 in aCCE aggregation level 4. A PDCCH for a UE#5 is transmitted on a CCEaggregation having CCE indices 8 and 9 in the CCE aggregation level 2.

The UE#3 acquires a 1^(st) resource index R1 based on the CCE index 2.Since the CCE aggregation level of the PDCCH for the UE#3 is 2, aresource index ‘R(1)+1’ cannot be allocated to any UE in a cell as aresource index. It is preferable to allocate the resource index ‘R(1)+1’as a 2^(nd) resource index R(2) of the UE#3 in terms of effective use ofresources. Therefore, when an offset which is a difference between the1^(st) resource index and the 2^(nd) resource index is 1, there is anadvantage in that resources can be effectively used.

However, a problem arises when the CCE aggregation level is 1 similarlyto the case of the UE#1 and the UE#2. This is because the 2^(nd)resource index of the UE#1 and the 1^(st) resource index of the UE#2become identical. In one method of solving this problem, the PDCCH isnot transmitted on a CCE immediately next to a CCE on which the PDCCHhaving the CCE aggregation level is 1 is transmitted. That is, the PDCCHis not transmitted on the CCE having the CCE index 1 in FIG. 18. Ofcourse, a problem of a case where the CCE aggregation level is 1 can besolved by using the aforementioned method of allocating the 2^(nd)resource index.

Even if the transmitter includes multiple antennas, the transmitter canoptionally operate in the single-antenna mode. When in thesingle-antenna mode, the transmitter including multiple antennas isregarded as if transmission is performed using a single antenna in areceiver according to a system requirement. That is, the transmitterincluding the multiple antennas can operate in the single-antenna modeor a multi-antenna mode. For example, an LTE-A UE having multipleantennas can optionally operate in the single-antenna mode. Thesingle-antenna mode includes operations of CDD, PVS, antenna selection,antenna turn-off, etc.

The BS can perform signaling on an antenna mode indicator for indicatingan antenna mode to the UE including multiple antennas. The signaling ofthe antenna mode indicator may be dynamic signaling or semi-persistentsignaling. PDCCH signaling is an example of the dynamic signaling. RRCsignaling is an example of the semi-persistent signaling.

It is assumed that the antenna mode indicator has a size of 1 bit, andthe antenna mode indicator set to ‘1’ indicates the multi-antenna mode,and the antenna mode indicator set to ‘0’ indicates the single-antennamode. However, this is for exemplary purposes only, and thus it is alsopossible that ‘0’ indicates the multi-antenna mode and ‘1’ indicates thesingle-antenna mode.

Hereinafter, a resource index allocation method related to an antennamode will be described.

A resource index can be allocated in a hybrid form of Method 1-2 andMethod 2-2. That is, to estimate the 2^(nd) resource index, an offsetvalue which indicates a difference to the 1^(st) resource index ispredetermined. For example, the offset can be predetermined to 1. Inaddition, the 2^(nd) resource index can be determined according to theantenna mode indicator.

If the antenna mode indicator is ‘1’, the multi-antenna mode is assumed.In this case, two resource indices are required. A 1^(st) resource indexR(1) corresponds to a 1^(st) CCE index. A 2^(nd) resource index can beacquired by using a predetermined offset according to Equation 20 below.

R(2)=R(1)+offset=R(1)+1  

Equation 20

If the antenna mode indicator is ‘0’, the single-antenna mode isassumed. In this case, one resource index is required. The resourceindex may correspond to the 1^(st) CCE index. In this case, the antennamode indicator indicates the antenna mode, and a resource index specificbehavior can be interpreted in a determined format.

On the other hand, the 1-bit antenna mode indicator can be renamed to anoffset field indicating the offset. In this case, if the offset fieldvalue is ‘0’, the offset is 0, and if the offset field value is ‘1’, theoffset may be ‘1’ or a predetermined value. It can be interpreted suchthat the antenna mode is the multi-antenna mode when two resourceindices are different due to the offset, and the antenna mode is thesingle-antenna mode when the two resource indices are identical.

Method for Information Transmission Through Multiple Carriers

In case of a multi-carrier system, there may be a case where informationis transmitted through multiple channels by allocating multipleresources. For example, there is a case where a UE receives DL datathrough each of a plurality of DL carriers and HARQ ACK/NACK istransmitted for each DL data.

FIG. 20 shows an example of a multi-carrier system having a symmetricstructure.

Referring to FIG. 20, the number of DL CCs is 2, and the number of ULCCs is also 2.

First, a DL CC #n is paired with a UL CC #n (where n=1, 2). That is,HARQ ACK/NACK for DL data transmitted through the DL CC #1 can betransmitted through the UL CC #1, and HARQ ACK/NACK for DL datatransmitted through the DL CC #2 can be transmitted through the UL CC#2.

The UE can transmit the HARQ ACK/NACK through a single antenna. In thiscase, only one resource index may be required for each UL carrier.

Alternatively, the UE can transmit the HARQ ACK/NACK through twoantennas according to OSRTD. In case of dynamic ACK/NACK, a resourceindex can be acquired by using a 1^(st) CCE index of a PDCCH for aPDSCH. Therefore, for transmission of the HARQ ACK/NACK for DL datareceived on the PDSCH through the DL CC #1, the UE acquires a 1^(st)resource index by using the 1^(st) CCE index of the PDCCH for the PDSCH.The UE can transmit the HARQ ACK/NACK on the PUCCH through the UL CC #1based on the 1^(st) resource index. The same is also true for the DL CC#2.

Second, the HARQ ACK/NACK for the DL data transmitted through the DL CC#1 and the HARQ ACK/NACK for the DL data transmitted through the DL CC#2 can be transmitted through the UL CC #1. As such, multiple ACK/NACKcan be transmitted through one UL carrier by using a bundling mode orresource selection to be described below.

(1) Bundling Mode

The bundling mode is when a plurality of pieces of information isbundled to transmit one piece of bundling information. The bundlinginformation is one piece of information that represents the plurality ofpieces of information. Herein, 1^(st) ACK/NACK corresponding to the DLCC #1 and 2^(nd) ACK/NACK corresponding to the DL CC #2 can be bundledto transmit representative ACK/NACK. For example, if the 1^(st) ACK/NACKand the 2^(nd) ACK/NACK are both ACK, bundling-ACK is transmitted. Inaddition, if at least one of them is NACK, bundling-NACK is transmitted.The bundling information can be transmitted based on one resource index.

A UE can acquire a Tx diversity by transmitting information through twoantennas according to OSRTD based on two resource indices.

(2) Resource Selection

The resource selection is a method of transmitting information byselecting one of two resources. When transmitting two ACK/NACKscorresponding to respective DL carriers, there may be two resourcescorresponding to the respective DL carriers. When applying the resourceselection, information can be transmitted by selecting one of the tworesources. In this case, a single-carrier property can be maintained.When the information is transmitted by selecting one resource,information can be transmitted by including information on the selectedresource.

For example, when there is a 1^(st) resource corresponding to a DL CC #1and a 2^(nd) resource corresponding to a DL CC #2, if it is assumed that2-bit information can be transmitted to each resource, the informationcan be transmitted as follows. However, this is for exemplary purposesonly.

000: 1^(st) resource (ACK, ACK) ON, 2^(nd) resource OFF

001: 1^(st) resource (ACK, NACK) ON, 2^(nd) resource OFF

010: 1^(st) resource(NACK, ACK)ON, 2^(nd) resource OFF

011: 1^(st) resource(NACK, NACK)ON, 2^(nd) resource OFF

100: 1^(st) resource OFF, 2^(nd) resource (ACK, ACK) ON

101: 1^(st) resource OFF, 2^(nd) resource (ACK, NACK) ON

110: 1^(st) resource OFF, 2^(nd) resource (NACK, ACK) ON

111: 1^(st) resource OFF, 2^(nd) resource (NACK, NACK) ON

When the UE transmits information through multiple antennas, OSRSM orSCBC can be applied.

FIG. 21 shows an example of a multi-carrier system having an asymmetricstructure.

Referring to FIG. 21, 1^(st) ACK/NACK for 1^(st) DL data transmittedthrough a DL CC #1 and 2^(nd) ACK/NACK for 2^(nd) DL data transmittedthrough a DL CC #2 have to be transmitted through a UL CC #1 which isone UL carrier. Since two ACK/NACKs corresponding to two PDSCHs have tobe transmitted, two resource indices are required. In this case, the tworesource indices can be allocated by using an offset. It can be achievedby simply replacing an antenna domain to a carrier domain in theaforementioned embodiment of the multi-antenna transmission.

For example, a 1^(st) resource index can be acquired from a 1^(st) CCEindex of a PDCCH for a PDSCH transmitted through the DL CC #1. A 2^(nd)resource index can be acquired from the 1^(st) resource index and anoffset.

However, only one difference lies in that when the same resource indexis indicated, an operation mode may be a bundling mode.

In case of the multi-carrier system having the asymmetric structure, theaforementioned bundling mode or the resource selection is applicable.

The aforementioned resource allocation method is applicable to aninformation transmission method based on all CDM/FDM schemes having sucha format as PUCCH format 1/1a/1b, format 2/2a/2b, etc.

FIG. 29 is a block diagram showing wireless communication system toimplement an embodiment of the present invention. A BS 50 may include aprocessor 51, a memory 52 and a radio frequency (RF) unit 53. Theprocessor 51 may be configured to implement proposed functions,procedures and/or methods described in this description. Layers of theradio interface protocol may be implemented in the processor 51. Thememory 52 is operatively coupled with the processor 51 and stores avariety of information to operate the processor 51. The RF unit 53 isoperatively coupled with the processor 11, and transmits and/or receivesa radio signal. A UE 60 may include a processor 61, a memory 62 and a RFunit 63. The processor 61 may be configured to implement proposedfunctions, procedures and/or methods described in this description.Layers of the radio interface protocol may be implemented in theprocessor 51. The memory 62 is operatively coupled with the processor 61and stores a variety of information to operate the processor 61. The RFunit 63 is operatively coupled with the processor 61, and transmitsand/or receives a radio signal.

The processors 51, 61 may include application-specific integratedcircuit (ASIC), other chipset, logic circuit and/or data processingdevice. The memories 52, 62 may include read-only memory (ROM), randomaccess memory (RAM), flash memory, memory card, storage medium and/orother storage device. The RF units 53, 63 may include baseband circuitryto process radio frequency signals. When the embodiments are implementedin software, the techniques described herein can be implemented withmodules (e.g., procedures, functions, and so on) that perform thefunctions described herein. The modules can be stored in memories 52, 62and executed by processors 51, 61. The memories 52, 62 can beimplemented within the processors 51, 61 or external to the processors51, 61 in which case those can be communicatively coupled to theprocessors 51, 61 via various means as is known in the art.

As such, a method and apparatus for effective information transmissionin a wireless communication system can be provided. When a plurality ofresource indices are required in a case where information is transmittedthrough multiple carriers when transmitting information through multipleantennas, a plurality of resource indices can be effectively allocatedto a transmitter. Accordingly, limited radio resources can beeffectively utilized. Further, reliability of wireless communication canbe increased, and overall system performance can be improved.

Additional advantages, objectives, and features of the present inventionwill become more apparent to those of ordinary skill in the art uponimplementation of the present invention based on the aforementioneddescriptions or explanation. Moreover, other unexpected advantages maybe found as those ordinary skilled in the art implement the presentinvention based on the aforementioned explanations.

Although a series of steps or blocks of a flowchart are described in aparticular order when performing methods in the aforementioned exemplarysystem, the steps of the present invention are not limited thereto.Thus, some of these steps may be performed in a different order or maybe concurrently performed. Those skilled in the art will understand thatthese steps of the flowchart are not exclusive, and that another stepcan be included therein or one or more steps can be omitted withouthaving an effect on the scope of the present invention.

Various modifications may be made in the aforementioned embodiments.Although all possible combinations of the various modifications of theembodiments cannot be described, those ordinary skilled in that art willunderstand possibility of other combinations. For example, thoseordinary skilled in the art will be able to implement the invention bycombining respective structures described in the aforementionedembodiments. Therefore, the present invention is not intended to belimited to the embodiments shown herein but is to be accorded the widestscope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method for receiving, by a base station (BS),information in a wireless communication system, the method comprising:transmitting a downlink (DL) data to a user equipment (UE); receiving afirst information sequence from the UE via a first antenna by using afirst physical uplink control channel (PUCCH) resource for the firstantenna, wherein the first PUCCH resource is based on a radio resourcewith respect to a physical downlink control channel (PDCCH) fortransmitting the DL data; and receiving a second information sequencefrom the UE via a second antenna by using a second PUCCH resource forthe second antenna, wherein the second PUCCH resource is based on anoffset and the first PUCCH resource, wherein the first informationsequence is generated, by the UE, based on first information, a firstcyclically shifted sequence and a first orthogonal sequence, and whereinthe second information sequence is generated, by the UE, based on secondinformation, a second cyclically shifted sequence and a secondorthogonal sequence.
 2. The method of claim 1, wherein the offset ispredetermined as
 1. 3. The method of claim 1, wherein the second PUCCHis addition of the offset and the first PUCCH resource.
 4. The method ofclaim 1, wherein the first PUCCH resource is based on a lowest controlchannel element (CCE) index of a CCE aggregation on which the PDCCH istransmitted.
 5. The method of claim 1, wherein the first PUCCH resourceand the second PUCCH resource correspond to a PUCCH format 1a/1b.
 6. Themethod of claim 1, wherein the first information sequence and the secondinformation sequence correspond to hybrid automatic repeat request(HARQ)-acknowledgement (ACK) as a response to the DL data.
 7. The methodof claim 1, wherein the first cyclically shifted sequence and the firstorthogonal sequence are determined from the first PUCCH resource, andwherein the second cyclically shifted sequence and the second orthogonalsequence are determined from the second PUCCH resource.
 8. A basestation (BS) in a wireless communication system, the BS comprising: amemory; a radio frequency (RF) unit; and a processor, coupled to thememory and the RF unit, that: controls the RF unit to transmit adownlink (DL) data to a user equipment (UE); controls the RF unit toreceive a first information sequence from the UE via a first antenna byusing a first physical uplink control channel (PUCCH) resource for thefirst antenna, wherein the first PUCCH resource is based on a radioresource with respect to a physical downlink control channel (PDCCH) fortransmitting the DL data; and controls the RF unit to receive a secondinformation sequence from the UE via a second antenna by using a secondPUCCH resource for the second antenna, wherein the second PUCCH resourceis based on an offset and the first PUCCH resource, wherein the firstinformation sequence is generated, by the UE, based on firstinformation, a first cyclically shifted sequence and a first orthogonalsequence, and wherein the second information sequence is generated, bythe UE, based on second information, a second cyclically shiftedsequence and a second orthogonal sequence.
 9. The BS of claim 8, whereinthe offset is predetermined as
 1. 10. The BS of claim 8, wherein thesecond PUCCH is addition of the offset and the first PUCCH resource. 11.The BS of claim 8, wherein the first PUCCH resource is based on a lowestcontrol channel element (CCE) index of a CCE aggregation on which thePDCCH is transmitted.
 12. The BS of claim 8, wherein the first PUCCHresource and the second PUCCH resource correspond to a PUCCH format1a/1b.
 13. The BS of claim 8, wherein the first information sequence andthe second information sequence correspond to hybrid automatic repeatrequest (HARQ)-acknowledgement (ACK) as a response to the DL data. 14.The BS of claim 8, wherein the first cyclically shifted sequence and thefirst orthogonal sequence are determined from the first PUCCH resource,and wherein the second cyclically shifted sequence and the secondorthogonal sequence are determined from the second PUCCH resource.